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Study Unit

Gun Sights

iii

In this study unit, we’ll explain the design,

function, and installation of metallic and

optical gun sights. Following a brief history

of gun sights, we’ll address metallic rifle

sights, shotgun beads, and pistol sights.

We’ll present gun sight installation procedures and identify

the tools the job requires.

Next, you’ll learn about the development of and uses for

optical sights (scopes) for rifles, slug shotguns, and pistols.

Then, just as for metallics, we’ll detail installation

procedures.

In the final sections, we’ll address bore and final sighting,

drill and tap procedures, bolt alterations, and safety

replacement.

When you complete this study unit, you’ll be able to • Summarize the history of gun sights, identifying hallmark

developments in their evolution

• Explain the design, function, and installation of metallic andoptical sights

• Explain how to bore sight

• Explain how to sight-in rifles and pistols

• Identify correct drill and tap procedures

• Describe the process of bolt alteration

• Describe how replacing safeties often facilitates scopemounting

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METALLIC RIFLE SIGHTS: A LINE OF ACCURACY 1

Metallic Sight Development 2Metallic Sights for Modern Rifles 6Installing Metallic Rifle Sights 13Installing Dovetail-mounted Open Sights 16Zeroing and Adjusting Metallic Rifle Sights 20

HANDGUN SIGHTS: PRECISE ALIGNMENT 24

Fixed Sights 24The Paine Sight 25The Patridge Sight 26Adjustable Sights 27Dots, Outlines, and Inserts 28Glow-in-the-dark Sight 28Ribs 29Installing Handgun Sights 29Shotgun Beads 34Installing Beads 37

SCOPES: A BETTER LOOK 40

History and Development 40Functions and Features of Rifle Scopes 45Pistol, Shotgun, and Air Gun Scopes 53Reticles 58Mounting a New Scope 59Scope Installation 65Attaching the Mount 66

DRILLING AND TAPPING 69

Drill and Tap Procedures 71Attaching the Rings 78Positioning the Scope 79

SIGHTING-IN 83

Bore Sighting 84Final Sighting 87Bolt Handle Alteration for Scope Mounting 90Procedure 91Safety Replacement for Scope Mounting 93Installation Procedures 94

SELF-CHECK ANSWERS 97

EXAMINATION 101

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METALLIC RIFLE SIGHTS: A LINEOF ACCURACY

History doesn’t record who invented the gun sight, and we

generally believe that shooters seldom used sights over the

two or three centuries following the first shots down range.

Accordingly, the ancient matchlocks, harquebuses, and

wheel-locks couldn’t have been very accurate. The shooter

simply pointed the barrel rather than aiming, and, if the

target was close enough, the shooter may-or may not-have

hit the target.

Even so, while gun sights were exceedingly rare, evidence

exists of their use. In The Book of Rifles (Stackpole Books,

Harrisburg, Pennsylvania, 1960) author W. H. B. Smith

reports that medieval German manuscripts document the

use of front and rear sights by target shooters to ranges as

long as 200 meters as early as 1500. You can see examples

of such early sights on museum relics and in archival draw-

ings. These sights were finely crafted works with minute

adjustments for both elevation and windage. The sights could

have contributed to remarkable accuracy if the guns on

which they were mounted were equally capable. Some early

sights incorporated such advanced features as

• Rear apertures (tiny peepholes set close to the eye)

• Hooded fronts (a circular covering of the vertical bead or

post at the muzzle)

• Threaded adjustment tracks complete with calibrated

settings

All are advantages seen in the highest quality match sights

today (Figure 1).

Gun Sights

We can only guess at the effectiveness of the early sights, but

clearly some gun makers enlisted the age-old concept of

using two reference points to establish a straight line. The

old revelation is that you can “create” a straight line using

your eye to sight on two given points, be they sharpened

sticks, notched wood or pottery, or even pointy rocks.

Certainly early builders used such a fundamental sight

premise. By the time of the great Greek and Roman empires,

the science of surveying had developed the principle. The

principle is simple: After aligning two positive, stationary

references, it becomes possible to extend that line to a third

point. In the case of guns and shooting, that third point is the

target. Hence, the reliance on front and rear sights working

in tandem, even as we continue to use them today, is simply

recognition of an immutable law of physics. Each time a

shooter aligns front and rear metallic sights on a target, he

or she creates a line (Figure 2).

Metallic Sight Development

While the knowledge of sights was fairly widespread, the

great majority of guns through the end of the eighteenth cen-

tury had none. It’s unlikely that the early smoothbore mus-

Gun Sights2

FIGURE 1—Although this early matchlock rifle carries sights, it wasn’t very accurate.

FIGURE 2—The principle of extending a straight line from the eye through two fixed points and then on to a thirdpoint-the target-is the basis for all metallic sight functions.

Gun Sights 3

kets would have benefited from mounted sights. Great armies

of the line squaring off in pitched battle wielded these military

arms. The emphasis was on reloading speed and a high rate

of fire-not precision.

Early Hunting Sights

Perhaps the most common sights of the era were those found

on the better hunting guns, first the German Jaegers and

then American long rifles (Figure 3).

Compared to finely wrought examples occasionally seen on a

weapon made for some duke or prince, they were somewhat

crude fixtures. In their most common form, they consisted of

a shallow V- or U-shaped notch for the rear sight-the one

closest to the eye-teamed with a simple rounded bead front

sight positioned at the end of the barrel.

Even today, such a combination is preeminent, and is com-

monly referred to as an “open” sight. The shooter simply

centers the bead in the notch and imposes the alignment

over the target.

The Pivoting Ladder

Throughout the first half of the nineteenth century, the

function of rifles changed dramatically. Emphasis shifted to

accuracy, and with that shift came the proliferation of sights

on virtually every rifle. Long-range shooting became a much

more viable art that depended on adjustable sights. The rear

notch remained in vogue. However, by the time of the Civil

War, arms makers like Sharps, Maynard, Enfield, and

Spencer had addressed the adjustment demand by mounting

the notched sighting piece on a pivoting “ladder.”

FIGURE 3—Sights like the ones mounted on this early American long rifle were rather crude fixtures.

By raising the ladder (which actually served as a track for a

sliding notched crosspiece) up off the barrel, the rifle would

place its shots higher, that is, achieve impact at longer dis-

tances. The adjustment simply required that the shooter

elevate the muzzle to align the sights. Thus, the ladder-type

rear sight, marked off in graduated settings that indicated

the increasing range, made it possible to shoot quite far with

reasonable accuracy. Indeed, some sights of the post-war

years were calibrated to 800 yards or more.

A ladder (sometimes referred to as a “leaf,” though that term

more frequently designates any notched sight piece) could be

attached to the gun and worked in different ways. Perhaps

the most recognizable type was hinged at the rear and was

simply stood up vertically for use. The sighting notch was

held in place by a set screw or spring-loaded “ears” that were

squeezed to free it to move to another setting.

Tangent Sight

Another ladder/leaf style worked on a lever principle (Figure 4).

In this type the sight leaf serves a dual purpose: its notch is

built in as a fixed end piece, and it acts as a guide for a slid-

ing jack. As the jack moves forward in contact with a ramp-

like base, the entire piece angles upward. The closer the jack

gets to the top of the ramp, the greater the elevation of the

rear sight, and consequently the shot. It’s easy to see how

this type is braced more rigidly, and therefore is more durable

than the pivoting ladder. Both designs proved so useful that

in some form they were continually employed into the modern

era on such advanced rifles as the 1903 Springfield (vertical

type) and Mauser 98 (vertical and ramp combined).

Gun Sights4

Gun Sights 5

The Aperture or “Peephole” Sight

Shooters soon devised another way to use the ladder sight,

this time as an elevator for a sliding peephole, or aperture.

Somewhere along the line they learned that sighting through

a small opening positioned close to the eye produced excel-

lent results. The rear sight no longer obscured a significant

amount of the field of view-so long as the peep was large

enough and/or close enough. Even better, the eye reacted

naturally to the peep, centering itself instantly while looking

through to the front sight and target beyond (Figure 5).

In all two-component sight systems, the front sight must be

the primary focus if the sights are to deliver their inherent

accuracy. While the peep won’t compensate for poor shooting

fundamentals, it does make sight alignment largely an auto-

matic process. By all accounts, peep sights were and still are

the fast track to accuracy.

Perhaps no one has used peep sights to such devastating

effect as the buffalo hunters. To get the peep close to the eye

where it would do the most good, they mounted the folding

ladders on the tang straps of their heavy Sharps and

Springfield rifles. Attached to and sliding on the ladder was a

rather large, coin-like metal disc drilled with a tiny hole.

FIGURE 4-This Mauser “foldingleaf” or “ladder” is typical ofthe type outfitted on militarybolt-action rifles in the yearsleading up to World War II. Youcan adjust elevation to morethan 1,000 yards.

From ranges up to 1,000 yards, the professional hunters

employed these rifles and tang sights to slaughter the bison

with terrible efficiency.

Eventual improvement came to tang sights by substituting a

solid stem for the traditional ladder. The peephole was then

mounted on the stem or incorporated into the design as a

rounded end piece. The stems were usually threaded and

set into a knurled sleeve, which was turned to make very

exact elevation adjustments. At the pivoting base was a

screw that moved the peep laterally to adjust for windage.

This type of sight was often mounted on the turn-of-the-

century Winchester and Marlin lever-actions where it

complemented the standard-issue open sights.

Metallic Sights for Modern Rifles

Before continuing the discussion of later peep/aperture

sights, we should consider two other developments. The first

is the front sight, which takes a few basic forms: bead, blade,

post, or aperture.

Gun Sights6

FIGURE 5—Aperture sightsare prevalent among competi-tive shooters because theytend naturally to center thefront sight as well as sharpen-ing the focus. The micrometerfine-tuning on this model iscapable of 1/8 minute-of-angle (1/8 inch at 100 yards) adjustments.

Gun Sights 7

The Front Sight

Small, rounded beads are the most common front sights.

You’ll sometimes find them used with one of the other types-

for example, when mounted atop a blade. The blade and post

are very much alike, both appearing as thin rectangles rising

at the muzzle. The blade simply comes to an edge while the

post is flat-topped. The front aperture, also called globe front,

is a thin ring.

While you’ll encounter almost any combination, it’s often

helpful to mate front and rear sights with complementary

profiles. When using a U-shaped rear notch for example, the

rounded bead is a good match, for it appears as a ball floating

in an oval field. This combo works well for hunters who have

to line up shots quickly, though it does have range limitations

and tends to obscure much of the target. A V-notch works

well with a sharp blade to make relatively fast, accurate shots

at longer ranges by covering much less target. A post is the

right shape for a square notch when sight alignment is diffi-

cult. It’s also appropriate when the target is so close or so

large that it matters little if quite a bit of it is blotted out. The

post is a favorite of pistol shooters. Front and rear apertures

team up to make concentric circles around a bulls-eye, a

rather specialized sight that’s ideal (and intended) for compe-

tition shooting. The idea with all types is to present the front

sight perfectly centered in the rear opening.

We should point out that other arrangements of such vari-

ables are useful and popular in certain situations. The

aperture-and-post has been the standard arrangement on

U.S. military rifles for almost a century, providing soldiers

with an uncluttered field of view and a front sight that’s

substantial and easily seen.

Making the front sight more visible has always been a concern.

Held out away from the eye, front sights that are usefully

small tend to fade as the light dims. For hunters who use

metallic sights, the ability to see the front sight largely deter-

mines their time in the field.

Since the early days of metal sights, shooters have doctored

their front sights by various means to make them brighter. A

common strategy has been to inlay a post or blade with some

luminous material like brass, ivory, or recently, plastic.

Beads made entirely from these substances also help to

solve the problem. Today’s shooters often resort to white

or Day-Glo orange paint on the rearward face.

The problem with all such remedies comes when the sun is

strong and the reflection from a bright front sight produces a

glare that makes it difficult to see. This is something that can

also occur with very shiny blued sights. Match shooters, sub-

ject to eye fatigue during long events, insist on nonreflective

sights and sometimes dull theirs with lampblack, a blacking

agent, or by scorching them with a lighter.

Another approach is a sight hood such as the one used to

support front aperture rings, so long as it’s big enough to

permit plenty of light (Figure 6).

Competition rifles often carry both blackened sights (which

contrast nicely with light-colored target sheets) and hoods,

while a hunting gun may benefit from a hood combined with

a luminous bead or blade. Many military rifles, including the

M1 and M16, come with upraised “wings” that shield the

front post without actually hooding it.

Gun Sights8

FIGURE 6—Globe front sightsare the perfect complementfor aperture rears. Hooded toprevent distracting glare, theycan be fitted with a widerange of inserts. The ring orfront aperture insert is idealfor centering round bulls-eyes.

Gun Sights 9

The Rear Sight

The second development to consider is the many variants

of the basic notched rear sight leaf. So far, we’ve simply

referred to notches’ general outlines, but it’s also important

to note the specialized forms some have taken, particularly

the ones still being used today (Figure 7).

The buckhorn sight. A distinctly American rear leaf, with

a wide following in the early days of lever-actions, was the

buckhorn. This sight got its name from sides that curved

up and in, vaguely copying the shape of white-tailed deer

antlers.

Rather than a simple notch, the buckhorn sight design left a

large central opening (sometimes including a tiny “V” at the

bottom). In a sense, the buckhorn attempted to combine the

notch and aperture, but from its customary forward mount

atop the barrel it tended to cover up too much of the target.

An improvement to this approach was the semi-buckhorn,

which begins to copy the shape but has much shorter “horns”

that don’t curve inward and form a broad “U.” Today’s rear

sights sometimes consist of a semi-buckhorn-shaped frame

onto which various exchangeable leaves with varying notches

attach.

The express sight. Another variation on the notched leaf

is the express sight, which offers an even wider taper than

the semi-buckhorn. It takes the form of a very shallow “V,”

whose sides run out to the corners at an extreme angle. As

the name suggests, the express is the fastest metallic sight to

bring into use, though it’s somewhat lacking when a shooter

requires long-range precision. The express sight’s speed,

however, has made it the top choice for hunting dangerous

game at close range. The finest English doubles (and other

large-bore rifles) frequently have very elaborate express

FIGURE 7—Rear sight blade styles include (from left): express, buckhorn, and semi-buckhorn.

sights containing a number of folding leaves. Arranged in

increasing heights, the leaves enable the shooter to select the

correct one for a particular distance. Meanwhile, the higher

leaves for longer ranges remain folded flat against their

mount. The mention of express sights is synonymous with

African hunting.

Most rear leaf sights are adjustable for elevation but only the

better ones for windage too. Commonly, if windage adjustments

are available, they’re built into the mount. Usually, a spring-

tempered base lies horizontally along the barrel and is fixed

by screws or a dovetail union at its forward end. The rear of

the base may not be attached, but spring tension holds it

down.

You adjust the elevation by forcing the spring arm upward.

Sometimes you can insert a screw, lifting the base as it

turns, but more often you change elevation by pushing a

stepped wedge under the sight. Other times you angle the

base upward and the fitted leaf simply slides forward and

locks with a screw.

When you use exchangeable notched blades, the screw holes

provided for their attachment elongate to supply the adjust-

ment. All of the adjustment provisions work adequately, but

many lack precise index marks to facilitate quick return to a

certain elevation.

When windage adjustment is provided, you can usually

achieve it by driving the entire sight-mount included-one

way or the other in its dovetail slot. This adjustment is drift

adjustment, and it’s the most common way for adjusting a

front sight.

Occasionally, you can laterally manipulate a rear leaf sight

with a screw. When this is the case, more precision is avail-

able than when using the drift method.

Rear leaf sights have always served their purpose reasonably

well. To this day, manufacturers outfit most factory rifles

with them. They’re often dressed up with a white triangle

or diamond pointing to the sight notch. No doubt, this has

made them even faster to use. As previously mentioned,

however, savvy metallic sight shooters long ago realized the

advantage of placing a peephole or aperture close to the eye.

Gun Sights10

Gun Sights 11

This realization triggered the development of sophisticated

yet versatile rear aperture sights that you could adapt to

practically any kind of modern rifle.

The Cocking-Piece Sight

With the advent of bolt-actions that offered no tang for

mounting, aperture discs and rings moved forward. Early on,

there was the cocking-piece mount, which attached directly

to the moving bolt plunger on rifles like the ‘03 Springfield,

the Krag, and the Mauser. Cocking-piece sights were essen-

tially scaled-down versions of tang-mounted sights, but even

the lightest model slowed the rifle’s lock time, thus negatively

affecting accuracy. Accuracy was further compromised

because the sight was mounted on a moving part and really

didn’t occupy a consistent position shot-to-shot. Moreover, it

was nearly impossible to practice good follow-through and to

call one’s shots when using a sight that jumped away.

Cocking-piece sights had their fans for several decades, but

by the 1950s they pretty much faded from the scene.

The Receiver Sight

A rear aperture style with much more staying power is the

receiver sight. As its name indicates, this sight mounts on the

receiver, usually as far to the rear as possible. Both hunters

and target shooters embraced it. Today, however, the scope

has just about made the premium metallic sights obsolete for

hunting. Still, a visit to any bulls-eye rifle shoot confirms

they’re still alive and well when not competing with scopes.

It’s the rare match shooter who tries to compete with any-

thing but precision receiver sights (Figure 8).

Several decades back, the development of receiver sights for

hunting and target shooting took different directions. In gen-

eral, the hunting models remained compact and rugged and

possessed fewer parts than the sophisticated match versions

with their built-in micrometer adjustments, calibration

scales, and eye shades.

Gun Sights

Aperture size and the way it’s presented to the eye are also

major differences. Hunters want a fairly large aperture that

allows them an unobscured view, and at the same time don’t

want available light limited any more than necessary. For

them, a peephole about inch in diameter, surrounded by a

narrow rim, is probably the best bet. Match apertures are

considerably smaller-.05 inch is a common size and some are

even tinier. Competition sights also change aperture size

quickly, either by accepting removable discs or by utilizing a

disk containing an adjustable aperture similar to those found

in camera lenses. Changing discs and adjusting the aperture

size enables shooters to meet range conditions.

Discs often come with an oversized light shield, or they’re

mounted inside a rubber eyepiece that blocks out all light

that’s not coming through the tiny hole. This also has the

effect of bringing the image of the target into very sharp

focus, again working like a camera lens.

The best receiver hunting sights were traditionally built on a

right-angle frame whose horizontal upper leg holds the aper-

ture out over the receiver in line with the bore. The vertical

leg extends down on one side where its mount attaches to

the receiver with screws. The entire unit remains extremely

compact, hardly two square inches.

Today, many of the same models are tailored to use top

mount screw holes, but they have the same low profile that

stands up to rugged use. Shooters often relied on such sights

as insurance not so many years back when scope durability

12

FIGURE 8—A great manyhunters once favored compactreceiver sights like this Lyman66. Besides being very light-weight and handy in heavybrush, they provided excellentaccuracy. Also, you can quick-ly remove many models fromtheir mounts when not in use.

Gun Sights 13

was still a dubious proposition. Adjustment knobs are pur-

posely down-sized so they won’t snag on brush or clothing.

Certain models feature a spring-loaded quick-release fixture

for removal from the mount base at the press of a button

(Figure 9).

Target aperture sights for smallbore rifles are fitted to mount

directly into grooves milled into the top of the receiver. Often-

times they sit relatively high above the bore line to correspond

with the elevated cheekpieces found on these rifles. Target

sights are comparatively heavy (6 1/2 ounces vs 1 1/2 ounces

for a hunting sight) and their large micrometer adjustment

knobs give positive clicks as fine as 1/8 minute of angle.

Installing Metallic Rifle Sights

At one time, the acquisition and installation of a new sight

were the most common reasons for visiting a gunsmith. To

some degree this is still true, although nowadays the request

is usually for scope installation. Unless the gunsmith works

closely with serious match shooters, the times the shooter

will ask the gunsmith to exchange a rifle’s factory metallic

sights for better ones will be few and far between. Nonetheless,

it’s a job that the gunsmith must handle with skill and preci-

sion if the sight is to perform up to its capabilities. Sloppy

work can permanently mar a gun, and while many shooters

can mount their own scopes, the general unfamiliarity with

metallic sights usually means that the shooter must turn the

job over to a professional.

FIGURE 9—Notice this receiv-er sight’s right-angle frame.

Prior to installation, you must determine the proper sight

height. For relative similarity between the point of impact

and aiming points, front and rear sights must be the same

height above the bore. To calculate the height, use a caliper

or micrometer to make three very exact measurements (preci-

sion is vital here, as a few thousandths of an inch could

make a big difference). Measure the barrel diameter at the

rear sight and divide by two. To this figure, add the meas-

ured height of the rear sight at the middle of its adjustment

setting. Then, measure the barrel diameter where you’ll

mount the front sight and divide by two. Subtract the for-

ward barrel figure from the rear barrel/sight sum and the

difference is equal to the required height of the front sight.

For example, say the barrel diameter at the rear sight is

exactly 1.0 inch. Divide by two to get .5 inch. Then, add the

height of the rear sight, which is .5 inch. At this point we’re

back to 1.0 inch. Barrel diameter at the front sight measures

.8 inch, which divided by two is .4 inch. Subtract .4 from 1.0

(1.0 – .4) to get a difference of .6. The overall height of the

front sight must be .6 inch.

In practice, you must build up the front sight to match the

relatively high position of the rear. When you mount a basic

rear sight leaf directly to the barrel, a front bead, blade, or

post similarly mounted is often sufficient. However, when

you elevate the leaf or use a different type of rear sight, it

becomes necessary to raise the bead/blade/post with a

ramp. You attach the ramp, a rectangular piece whose face

angles back toward the shooter, to the barrel, and then you

attach the sight to the ramp. Combined, the ramp and front

sight meet the height requirement with a much stronger and

better-looking fixture.

You may see a barrel with an integral ramp, usually the work

of a custom barrel maker. This adds considerably to the

effort of forging the barrel, and therefore considerably to its

cost. Fortunately, add-on ramps are widely available, and

some even have the bead or blade incorporated into their

design. The leading makers of metallic rifle sights like

Williams and Marble offer extensive selections of front sight

heights and styles to work with various rear sights on just

about any modern rifle.

Gun Sights14

Gun Sights 15

Metallic sights attach to a rifle in several ways. Rear sights

are either held in place by screws, friction-fitted into a dove-

tail slot, or soldered (silver or soft depending on the sight and

gun) to the receiver or barrel. Front sights are secured by

screws, dovetails, and soldering as well, and in addition, a

blade or post may be inserted at the muzzle in a linear slot.

You frequently cut dovetail sight slots directly into the barrel,

but you may also machine them in a mount base joined to

the barrel by screws or an encircling band. Some front sights

are even fabricated with the bead/blade, a ramp, and the

band as a single made-to-order unit.

When substituting a new sight that’s the same type as the

old one, the gunsmith can almost always use the existing

screw holes or dovetail slots. You should check them, of

course, to make sure they’re in good condition; the threads

must be intact, and dovetail corners must be sharp. In cases

of extreme wear, retapping a hole or dressing corners with a

file may be necessary.

At the outset of any sight exchange work involving dovetail

mounts, remove the barreled action from the stock and brace

it in a padded vise. (This may also be necessary with certain

screw-on mounts.) Such reinforcement prevents possible bar-

rel damage. Always drive the old dovetail mount out from left

to right with the muzzle pointed away. Use a soft brass drift

punch or a nylon rod for all driving and tap only as hard as

necessary to move the sight.

With dovetails, mark the barrel with a felt-tip marker pen to

record the center point of the old sight. Make a correspon-

ding mark on the new sight, then drive it in-right to left-until

the two marks are just short of meeting. Make the final drift

adjustment after firing a few shots (preferably at close range,

say 10-15 yards), tapping it only as far to the left as needed

to line up the windage. This saves wear on the slot caused by

driving the dovetail back and forth and will ensure that the

sight remains sufficiently tight. If the fit of a new sight is a

little loose, use a coating of solder tinned to its bottom sur-

face to take up the slack. Be sure to file the solder smooth

before installation and clean up the edges afterward.

Gun Sights16

For some sight mounting jobs it will be necessary to provide

a dovetail slot where none currently exists. It is best, when

cutting a dovetail into a barrel or receiver, to use a milling

machine and the properly sized sight base cutter. The stan-

dard for rifle sights is inch with a 60 degree shoulder.

Machine tools aren’t an absolute necessity; however, you can

fashion a perfectly acceptable dovetail with a few hand tools.

However, you must do it with extreme care, and many gun-

smiths disdain making this alteration to a gun. Their feeling

is that it weakens the barrel and so doing causes it to vibrate

much more than usual, thereby reducing accuracy. As an

alternative, you can provide dovetail slots by substituting

screw-on or sweat-on (soft solder) bases or a barrel band

precut with dovetails. Nevertheless, because dovetail-mounted

open sights remain prevalent, we’ll now describe the

procedure.

Installing Dovetail-mounted Open Sights

Sight dovetails have the standardized dimensions of .090

inch deep and .375 inch wide along the lower face. Before

getting started, measure the barrel to ensure that it’s thick

enough to take the cut. You should leave as much metal

above the bore as you plan to take away.

It’s important that you make the cut exactly perpendicular to

the bore. The easiest way to do this is by snugging the barrel

in a padded vise, then rotating it until the existing rear sight

is level (check with a machinist’s level). If this isn’t possible,

use a pair of try squares to true the action vertically. Rest

the head of one square on a level surface and align its blade

with the blade of the other square. Then, rotate the barrel

until the flat underside of the receiver lines up with the head

of the second square.

For clean, precise hand cuts we advise you to employ some

kind of guide tool, such as the SPL Dovetail Guide (Figure 10).

This is a handy, square-sided device that clamps onto the

barrel and offers an open tooling slot on its top face that’s

perfectly sized (depth and width) and angled for dovetail

dimensions. Its flat sides simplify leveling and the hardened

steel prevents overcutting. The user merely makes cuts

(described below) through the slot.

Gun Sights17

In the absence of a machined guide,

begin by measuring the narrowest part of the sight dovetail

and transferring this dimension to the barrel using a sharp

scribe. Use a try square to ensure that you make the scribing

marks squarely on the barrel. Even better is to inscribe the

dovetail’s entire profile on the barrel. At this point, just

enough of the barrel’s upper surface should project above the

vise jaws so that the jaws help regulate the depth of the cut.

Use a hacksaw to begin the metal removal.

Caution: Be sure not to penetrate to the full .090 inch depth.

Make several of these closely spaced, short hacksaw cuts

inside the scribing marks.

You remove the remaining steel and shape the dovetail with

a 60 degree, 3 square file. It’s best to grind one side of the

file smooth beforehand

so that only one sur-

face is cutting at any

one time and turn

down the smooth side

(Figure 11).

FIGURE 10—The SPL DovetailGuide helps you cut clean andaccurate dovetails every time.

FIGURE 11—After carefullyscribing the outline on the barrel and making a number of initial cuts with a hacksaw,you shape a dovetail sightmounting slot with a 60 degree file. At least one side of the file should be smooth to avoid unintended cutting.

Ideal for cutting dovetails is Brownell’s Sight Base File, spe-

cially made for this job. It comes with just one cutting face;

the other two sides are smooth, eliminating the possibility of

unintentionally enlarging the cut. Undercut both sides grad-

ually, switching from one to the other to make sure they stay

even, and as the slot takes shape, closely compare and fit

it to the actual sight dovetail. Keep in mind that the slot

should taper a tiny bit-the final cuts make the right side a

few thousandths of an inch wider to ease the dovetail in and

out of the cut.

Many rear aperture sights are side-mounted to the receiver

wall with screws, except on certain match rifles where receiv-

er top grooves have been provided. It’s vital that you install

the mount square to the receiver so that the aperture arm’s

position is exactly perpendicular to the bore. The location of

the mounting holes governs this. Ideally, you locate, drill,

and tap screw holes using a professional jig setup like the

Forster Universal Sight Mounting Fixture or Brownell’s SSR

Mounting System. These tools ensure correct alignment with

the bore, square screw holes to the action, and guide drills

and taps with hardened bushings so that the holes are clean

and straight. When a drill jig isn’t available, it’s possible to

square the sight base to the receiver with a try square. Place

the square’s head on the true undersurface of the receiver

and line up the base with the blade. Clamp the base securely

in this position with a C-clamp, and scribe the location of

one of the holes. Remove the base and center punch the

mark, then drill the hole with a No. 31 drill and tap for a

6-48 screw. Install the sight, tightening the screw firmly.

Now, use a No. 28 drill to mark the spot of the second hole.

It will center in the sight base hole, thus ensuring precise

registration with the first hole. Don’t overdo it with the No.

28 drill-just enough to provide a center. Then remove the

sight, center punch, and finish drilling with the No. 31. Tap

the hole and install the sight.

Caution: Only use hollow-ground screwdrivers with parallel-

sided blades and be certain that the blade completely fills the

screw slot. If you don’t have the correct blade, grind one to

fit. A mismatched screwdriver blade invariably jumps the

slot, thus damaging the screw head and scratching the metal

finish. Screws extending through the receiver wall must be

Gun Sights18

Gun Sights 19

filed flush. Use a quarter-inch rattail file for this and finish

with a piece of emery paper wrapped around the file.

All sight-mounting screws should be extremely tight and

coated with a few drops of Loc-Tite or a similar thread-locking

compound before final installation. Use sparingly and wipe

away any excess before it has a chance to seep onto other

surfaces or parts.

Although it’s permissible to drill into receivers when mount-

ing sights, you should never penetrate the bore when drilling

holes for barrel sights. Quite simply, this ruins the barrel.

It’s essential to determine how deep the hole can be in a

given spot. This may change from one end of the barrel to

the other since many have thicker walls at the breech than

at the muzzle. Prior to any drilling operation, measure the

barrel thickness at the spot you’ll drill using a caliper,

divider, or micrometer where possible.

Most quality drill presses come equipped with a depth-

indicator scale. It’s a good practice to set up the drill so

that it can penetrate no deeper than 1/32 short of the final

desired depth. Take great care when drilling barrel-sight holes,

checking frequently with a high-quality depth micrometer.

The optimum holding power of a 6-48 screw is attained at

.137 inch; for the 8-40 it is .162 inch.

In thin-walled barrels, it’s not always possible to provide this

much internal thread while taking care that the screw doesn’t

bottom out in the hole. Carefully note where the screw head

is when the screw begins to tighten. If it’s not fully seated

against the sight body, remove the screw and carefully grind

a little off the end.

Sweat-on (soft-soldered) sight bases and ramps will often be

reinforced with a screw, but it’s the heat-bonding of the met-

als with the solder that’s intended to secure the sight.

However, there are few things to keep in mind when using

this method to install sights. Foremost, you must mount the

bases squarely to the barrel. To do so, true the barreled

action in the vise with try squares as previously described.

Place the sight in its approximate location on the barrel and

use a level to determine its exact position. Scribe the outline

of the base on the barrel as a guide for the sweating operation.

It is best to use a sight/ramp soldering jig as offered by

Brownells and other firms to maintain the necessary constant

pressure during heating. It’s difficult for a standard C-clamp

to prevent sight-base slippage when the solder softens. Remove

excess solder with a rag and check to make absolutely sure

the sight is level before the joint begins to harden.

Zeroing and Adjusting Metallic RifleSights

One fundamental principle governs sight adjustment: Always

move the rear sight in the direction that you want the shot

to move. If, for example, a shot group prints to the left of

the bulls-eye, move the rear sight to the right; when shot

placement is low, raise the rear sight. When you apply this

principle to open or aperture rear sights, it means that you

must move the sighting notch or peephole. Conversely, on

those occasions where it’s necessary or preferable to adjust

the front sight, you must move it in the opposite direction of

the desired impact change.

Some open and rear-leaf sights are dovetail mounted and

have no provision for adjustment other than drifting the

dovetail in its slot. This adjusts for windage only. You make

drift adjustments the same way that you remove an old dove-

tail-by driving the sight with a mallet and brass or nylon

punch. Not only is this a very inexact technique, it could

damage the rifle if the shooter doesn’t take pains to do it

right.

When making windage adjustments, avoid marring the stock

or metal finish by first laying the rifle on a table or bench

covered with a rubber mat or old carpeting. Rather minute

changes in the sight’s position can produce significant shifts

down-range, so tap the sight lightly and move it only a little

at a time.

Elevation adjustment for most open sights is controlled by a

screw or a notched sliding elevator. Occasionally a sight is

made to take replaceable leaves that you can shift up and

down in their oblong screw slots. All of these are fairly easy

to use, but the shooter must work with them to become

familiar with the impact changes they produce. Understand

Gun Sights20

Gun Sights 21

too that elevation is set for a particular distance, so shots

will no longer be zeroed when firing at longer and shorter

ranges.

The key to adjusting open sights is to patiently make the

adjustments in very small increments. Also, it’s wise to begin

the sighting-in process at very close range-certainly no farther

than 50 yards-and on a rather large target. Most experienced

shooters prefer to adjust windage first. That way the shots

are hitting on the target’s central axis. The good thing about

zeroing open sights is that they are very sturdy and probably

won’t need to be dealt with again so long as the shooter and

load remain the same.

Whether for hunting or competition, rear aperture sights are

usually designed with precise adjustment capability. This

makes them easier to zero than open sights. Because they’re

inherently more accurate, the shooter usually needs to fire

fewer sighting-in shots than is required for open sights

(Figure 12).

Aperture sight adjustments are calibrated to provide impact

shifts in a fraction of one minute-of-angle, a geometric unit

for measuring a circle. For the shooter, it’s necessary to

understand that one minute-of-angle nearly equals one-half

inch at 50 yards, one inch at 100 yards, two inches at 200

yards, etc. When sights adjust in one-quarter minute clicks,

the practical effect is to change shot placement one-quarter

inch at 100 yards, one-eighth inch at 50 yards, one-half inch

at 200 yards, and so on. (One-quarter minute clicks is the

FIGURE 12—A multileafnotched rear-sometimesreferred to as an express sightwhen found on large-caliber“safari rifles”-is the mostsophisticated type of opensight.

most common degree and terminology for such increments.)

If, for example, a 100 yard shot group is two inches high

and 11/2 inch left, the shooter would zero it by rotating the

adjustments knobs to move the aperture down eight clicks

and right six clicks. Suppose the group is off-target by the

same amounts at 200 yards. Then it would take four clicks

down and three right to put the shots in the bulls-eye.

Be aware that not all aperture sights offer quarter-minute

adjustments (half-minute and eighth-minute are also avail-

able). Also be aware that the adjustment values are usually

figured on a 30 inch sight radius (the distance between front

and rear sights). When the sights are closer or farther apart

than 30 inches, the values will differ. Also, some less sophis-

ticated models may adjust by means of a sliding scale held in

place with a set screw rather than click-type knobs.

When the shooter learns what to expect from the adjust-

ments, he or she is able to use them quickly and efficiently

to allow for wind or additional range when hunting or in

competition. Because the knobs and scales are marked, the

shooter can quickly return the sight back to its original set-

ting. Again, it’s wise to sight-in at 50 yards or less first, then

correct for the desired zero range by moving the target and

firing at that distance.

Gun Sights22

Gun Sights 23

Self-Check 1

At the end of each section of Gun Sights, you’ll be asked to pause and check your under-standing of what you have just read by completing a “Self-Check” exercise. Answering thesequestions will help you review what you’ve studied so far. Please complete Self-Check 1 now.

Indicate whether the following statements are True or False.

_____ 1. To get peep sights closer to the eye, buffalo hunters mounted them on the tangstrap of their rifles.

_____ 2. When zeroing metallic sights, you should begin the shooting at 50 yards or less.

_____ 3. The aperture of a target competition receiver sight is usually quite large.

_____ 4. You should taper a dovetail sight mounting slot so that the left side is a few thousandths of an inch larger.

_____ 5. In essence, when a shooter aligns front and rear sights, he is creating a straightline to the target.

_____ 6. To make front sights more visible, shooters have resorted to moving them closer tothe rear sight.

_____ 7. German target shooters were using front and rear rifle sights as early as 1700.

_____ 8. The development of ladder-type rear sights made it possible to sight-in for as far as800 yards.

_____ 9. On certain sight mounting jobs, it’s necessary to drill into the rifle’s bore.

_____10. Front sight styles include express, buckhorn and semi-buckhorn.

Check your answers with those on page 97.

HANDGUN SIGHTS: PRECISEALIGNMENT

In no type of shooting is it more important and as difficult to

use the sights properly than when firing a handgun. We can

sum up the reason for this in an oft-heard pistol shooter’s

phrase-short sight radius. As noted in the section on rifle

sights, sight radius simply means the distance between front

and rear sights. Obviously, this distance is much shorter on

a handgun. Consequently, there is far less room for alignment

error since it only stands to reason that any variance magni-

fies the barrel’s angle off the intended aiming point. The

result down-range is inaccuracy.

As difficult as it is to attain proper sight alignment with a

handgun, it’s probably even harder to maintain it. A firearm

held out in front of a shooter will just never be as steady as

one braced against the shooter’s body. Though handguns are

every bit as old as long guns, perhaps even predating them,

the inherent problems of shooting them with any degree of

accuracy effectively stymied the development of their sights. It

was probably a foregone conclusion that these fast-handling,

easy-carrying guns were to be relegated to point-blank duty

and we couldn’t expect much more of them. This isn’t to say

that early handguns didn’t have sights. Many muzzle-loading

pistols were outfitted with front bead and perhaps some type

of rear notch or even both. No doubt these sights made them

far more serviceable. Still, muzzle-loading pistols and the like

weren’t much good any farther than one could throw them.

Fixed Sights

Not until the introduction of Colt’s cap-and-ball revolver

design and others like it did utility come to pistol sights. These

revolvers weren’t immediately more accurate than single-

shots of the time, but their ability to fire several shots rapidly

led to enhancements for making those shots more consistent,

one to the next.

Gun Sights24

Gun Sights 25

The early revolvers evolved with a sight setup that remains

the basic offering to this day. It originally consisted of a

small notch in the hammer for the rear sight and a thin

half-moon blade stuck to the barrel for the front sight. This

setup slightly improved when a shallow rounded groove in

the top of the frame became the rear sight.

Such sights are fixed. No adjustment is possible other than

visibly changing the sight picture or filing down the front

sight to move shots higher. (Remember, moving the front

sight up or down-in this case down-results in shots moving

in the opposite direction.) Because these open sights lack

adjustment capability, they pose certain problems for the

shooter. It becomes difficult to change loads, to shoot in

wind, or to cope with much variation in range. If for some

reason the gun doesn’t shoot well, it’s hard to ascertain if

the sights are to blame. Nevertheless, these sights are utterly

durable and the shooter can’t “rough” the off zero. Also, they

in no way hamper the shooter when drawn from a holster

or pocket. Furthermore, there have been countless revolvers

and small automatics over the years that have been

admirably accurate with such fixed open sights. We should

note also that aperture sights never caught on for handguns,

since the shooter’s eye is too far away to make much use of

a peephole.

In the late 1800s, when target shooting with all kinds of

guns was a sport that attracted widespread interest, there

emerged developments in handgun sights that had a pro-

found influence. Two top pistol competitors, Ira Paine and

E. E. Patridge, promoted distinctive designs, sometimes even

referred to as “Paine” or “Patridge” sights. You’ll find both

of these, or at least close derivatives, on a majority of the

handguns in use today.

The Paine Sight

The original Paine-type sight teamed a U-shaped rear notch

with a bead front. While the U notch remains quite common,

it’s rare to see a bead on handguns these days, and blades

(of many different shapes and sizes) are the clear choice of

contemporary pistol makers and shooters. On some current

models, the notch is built up off the frame in an integral pro-

jection or a soldered addition, and its shape may now be a V

or square. Whatever the variation, the blade front and fixed

notched rear remain as basic factory equipment on a wide

range of handgun models. It’s especially prevalent on smaller

pieces intended solely for very close range work (Figure 13).

The Patridge Sight

The Patridge, which remains quite popular with many hand-

gunners, match shooters in particular, is fundamentally

identical to its earliest versions. It offers a square or rectan-

gular rear leaf bearing a square notch. The front is a blunt,

high, flat-sided post that’s often (but not always) perpendicu-

lar to the barrel. E. E. Patridge felt that the sharp angles on

top and the narrow clearances between the post and each

side of the notch would give the fastest and most precise

sight alignment so crucial for a short-barreled gun.

Apparently he was right, for the Patridge system dominated

pistol competition for many years until the use of optical

devices superseded it. Even now, when the rules dictate

metallic sights, a Patridge front blade working with an

adjustable rear is the hands-down favorite.

Gun Sights26

FIGURE 13—Two enduringtypes of handgun sights arethe Paine (top), a shallow U-shaped groove and a frontbead, and the Patridge (bot-tom), with its high square-notched blade and squarefront post.

Gun Sights 27

Adjustable Sights

Match shooters were quick to demand adjustable sights, and

the gun makers soon responded. Companies like Colt and

Smith & Wesson devised sights (both front and rear) that

pivoted by some means and were held in place by set screws.

The shooter adjusted rear windage by manipulating a pair

of screws at either side of the sighting notch. At times it took

much perseverance to zero early adjustable sights, but they

could be made to shoot quite well and gave pistols a versatili-

ty they hadn’t previously possessed.

Where the first adjustable pistol sights were probably some-

what fragile, those that followed and the ones used today are

compact, rugged, and not likely to be thrown off zero even

with rough treatment. In their most basic form, current

adjustable pistol sights can only move laterally, usually by

the drift method, and therefore can only correct windage.

These aren’t for match shooting, of course, but you’ll find

them on many mid-size and larger revolvers and some auto

loaders, including many police and service weapons.

The better adjustable rear sights are now capable of fine-

tuning both windage and elevation (w&e), some even incorpo-

rating miniature micrometerlike mechanisms. Quite a few of

the factory w&e sights appear as compact cylindrical attach-

ments supporting notched sight leaves. Others, particularly

aftermarket offerings, are contained in low-profile, square

housings. On both styles, you make windage and elevation

corrections by turning separate adjusting screws, some of

which feature positive felt clicks like the ones in rifle receiver

sights and scopes.

When w&e rear sights are factory installed, they’re most likely

on the pistol maker’s top-of-the-line models. The finest of

these include Smith & Wesson’s factory rear sight and custom

versions from companies like Millett, MMC, Bo-Mar, and

Wichita. Obviously, they’re on the firing line when the top

bulls-eye, silhouette, and combat pistol competitors are

using metallic sights.

Dots, Outlines, and Inserts

Not an especially new idea but one that remains timely today

is the notion of adding some type of bright reference marks

to pistol sights. These can be valuable when shooting in dim

light, so they’ve been particularly useful for handgun hunters

and police.

Dots, which are usually white (alternately red or orange), can

be on either side of the rear notch and on the face of the front

post. Outlines are inlaid white or gold lines that highlight the

shape of the notch and occasionally extend up or form a cross

at the center of the post’s rearward face. Inserts, traditionally

made of brass or red plastic, are set lengthwise into a front

post and flush with its face. These also come in white, yellow,

green, and orange.

You should understand, however, that none of the high-

visibility markers actually define the true sight picture. All

are situated off the notch’s or post’s sharp black edges,

which must be finely aligned for ultimate accuracy. The

dots, outlines, and inserts function as guides that enhance

and speed up the alignment process.

Glow-in-the-dark Sight

Working on the same principle are ultrahigh-tech glow-in-the-

dark sights developed for military and law enforcement use.

These get their “glow” from a built-in source of tritium gas

that makes luminous dots or outlines. Conversely, glare from

any sight or visible surface can blur sharp edges and make

precise sight alignment impossible. To prevent this, most

sight surfaces that face the shooter are grooved, serrated,

beveled, or even checkered so that they can’t reflect distract-

ing light. Like rifle competitors, handgunners will dull sights

with lampblack or commercial blacking agents to eliminate

glare.

Gun Sights28

Gun Sights 29

Ribs

Originally a feature found on shotguns, rail-like attachment

ribs for pistols and revolvers provide a handy means for affix-

ing sights. Performing as on shotguns, they guide the eye

down the barrel to speed front sight acquisition. Ribs extend

along the top of the frame/barrel or slide in a wide selection

fitted for specific handgun models. Many ribs come outfitted

with top-quality adjustable front and rear sights, though they

can also be solely a mounting rail.

In an extreme application, international free pistol shooters

use a rib-like extension to position the front sight well out

ahead of the muzzle. This gives them extra sight radius,

which translates to increased accuracy. It’s obvious that

such an unwieldy appendage is impractical and undesirable

for handguns outside this highly specialized sport, but it

does show how ribs provide a gun more sighting versatility.

Installing Handgun Sights

Among handgun owners, a fair number will want to swap

factory sights for new ones. They’re certainly not in the

majority and generally won’t include casual plinkers or

one-gun householders whose pistol represents a means

of emergency self-defense. Furthermore, handgun hunters

these days are virtually unanimous in their adoption of

scopes. However, in places where target shooting is strong

or in shops that service police, security, or military personnel,

there will be a steady call for replacement sights. Also, heavy-

recoiling calibers and magnums that are fired a lot have a

tendency to shear small pins and screws in rear sight mech-

anisms, or to “shoot” loose front blades.

As with metallic rifle sights, there are a handful of common

installation methods. These include dovetail friction mounts,

screw attachment, soldering, and staking. Any of these meth-

ods will also work when employing a rib, although dovetail

and screw mountings are the norm. The ribs themselves are

usually affixed by a combination of dovetails, screws, and/or

soldering.

Fixed-sight pistols will rarely be subjects for rear sight

replacement since the original fixtures are virtually inde-

structible and the purpose of these guns make them unlikely

candidates for such customizing. However, in cases where

a shooter desires an alteration, one must devise a way to

attach a sight leaf to the existing rear sight. Where projecting

“ears” or some sort of sight leaf is present, you may be able

to solder a new leaf to the old one, filing the notch as

desired. On early Colt revolvers and others whose rear sight

is a basic top-strap groove, you must make a vertical relief

cut with a Dremel tool or small hand grinder to have some

flat surface on which to solder the new sight. This cut must

match the contour of the groove, not going too deep into the

frame lest the top-strap become weakened.

A much more likely scenario is to leave the rear sight intact

and replace the front. When the front sight is an integral bar-

rel forging, as on older Smith & Wessons, you can partially

ground it down to form a base. Then, slot it lengthwise to

accept a new blade. Make the slot initially with a hacksaw,

then widen and finish the cut with needle files. File-fit the

slot to the blade, extend it all the way down through the

base to the top of the barrel, and leave it a little tight. For

an extremely rigid installation that won’t loosen when you

shoot, secure it with a pair of hardened 1/32 inch drill-rod

pins driven through the base. (To do so, it will be necessary

to seat the blade first, then drill the pin holes.)

To replace Colt front sights and others that are soldered/

brazed into a barrel slot, it will be necessary to remove all of

the old blade at the outset. When any of it is still present-no

matter how little-grind off whatever remains above the barrel

and clean out the slot with a file. It’s then simply a matter of

inserting and silver-soldering the new blade in place.

Slot-mounted front sights are also common additions to

semiautos when you need more height to complement the

installation of a new rear sight. The latest versions are usually

rectangular, ramplike posts outfitted with perpendicular

mounting tenons that extend down into the slide. When no

slot previously exists for this installation, you can start one

by drilling a series of overlapping 3/32 inch holes just slightly

narrower than the width of the tenon. Join the holes and

Gun Sights30

Gun Sights 31

shape and finish the slot by filing, taking care to keep the

opening just a hair undersize to ensure a rigid fit. Silver sol-

der the new sight to the slide; afterwards, trim off any part of

the tenon that protrudes on the inside. For extra strength,

you can use drill rod pins to anchor the tenon/slide union.

The majority of handgun sight installation jobs involve

adjustable rear sights. Match shooters are well known

for experimenting with different models, and because the

adjustable sights often incorporate moving parts, from time

to time they come in for repair/replacement.

Swapping one basic dovetail-mounted unit for another is the

simplest rear sight conversion. This involves driving the old

part out of its slot with a brass or nylon punch. Always drive

the part from left to right with the muzzle pointing away and

then file the new one in its place (Figure 14).

Among the current selection of aftermarket sights, one can

find adjustable rear models made to fit factory dovetails on

most American-made and many foreign handguns. This, by

far, is the easiest, strongest, and least expensive alteration.

It’s crucial that dovetail mountings on hard-kicking guns

like the .45 ACP, 10mm, and all magnum calibers maximize

bearing surface contact. Check this by coating the slot sur-

faces with lampblack or carpenter’s chalk, fitting the sight,

then noting where the sight did and didn’t make contact. File

FIGURE 14—When removing adovetail-mounted sight, alwaysdrive it out from left to rightwith the muzzle pointing away.These slots are tapered a bitto the right side to facilitateinsertion/removal.

down all high spots until you achieve uniform contact. It’s

also wise to employ a secondary attachment method for dove-

tail mountings. Some current sights come with set screws

that bear on the dovetail floor. Similarly, you can stake the

sight securely into the dovetail with a sharp prick punch.

Alternate methods include tinning with soft solder (be sure

to cover both slot and mount) or using the prick punch from

inside the slide or top-strap to raise dimples on the bottom of

the dovetail.

A growing number of semiauto shooters prefer low-profile

“combat” rear sights. These mount very low to the gun to

minimize quick-draw interference and come in fixed, drift

adjustable (windage only), and fully adjustable versions

(Figure 15).

Full-adjustment models can sometimes require significant

alteration of the slide since they may fit too far to the rear to

utilize the factory dovetail. This requires cutting a new dove-

tail and, often, removal of metal from the rearmost portion of

the slide to allow clearance for an overhanging sight leaf. You

should perform such operations on a milling machine, but

first you must fill in the original dovetail by arc welding or

with a tight-fitting dovetail blank. Use a 65 degree cutter-in

the appropriate width-to make the dovetail and an end mill

cutter for the clearance cut. Make certain not to remove any

more metal than is absolutely necessary to clear the rear

of the sight. For more details on milling machines, see the

study unit entitled Basic Metalwork and Machine Tool

Operation.

Gun Sights32

FIGURE 15—Low-mountedadjustable rear sights havemade handguns significantlymore accurate and versatile.The best models areadjustable for both elevationand windage and come withpositive, micrometer-like“clicks.”

Gun Sights 33

Another adjustable rear sight commonly chosen for upgrade

jobs is the Smith & Wesson type with its elongated, spring-

like mounting base. Millet Co. fabricates fitted versions for

many current revolver models (including one for older S&W N

and K frames) as well as the Colt Gold Cup auto loader. The

base extends along the top-strap or slide like a partial rib

and is neatly attached by a mounting screw (Figure 16).

On guns that don’t already have the screw hole present for an

existing sight, you must drill and tap one. Always disassemble

autos or remove revolver cylinders before any drilling opera-

tion. Secure the slide or frame in a padded drill press vise or

a drilling jig that can handle pistols, such as Brownell’s SSR

Mounting System. Drill and tap for a 3-56 screw (or improve

this to a 5-40), and tighten it securely (as tight as possible

without snapping the screw). Be sure to use only a parallel-

blade hollow-ground driver that perfectly fits the screw head.

A sparing application of Loc-Tite or similar thread cement

will help ensure a lasting bond. Always trim off any part

of the screw that protrudes beneath the slide/top strap

undersurface.

You can adapt this same type of sight to Colt Government

models (and their clones) and other semiautos. This requires

inletting a shallow recess into the top of the slide so the base

FIGURE 16—Most adjustablerear handgun sights feature anelongated mounting tang fit-ted into an inletted slot at therear of the slide. A number ofmethods can secure the sightin place, and the most com-mon is probably with a screwthat extends down into theslide.

Gun Sights

will mount flush. Milling is certainly the faster way to accom-

plish this, but you can use a file so long as you carefully

center the work on the slide. Begin the cutting just behind

the ejection port and just wide enough to snugly accept the

base. You must cut a step (by milling or with hacksaw and

file) into the upper rear corner of the slide to accommodate

the sight body. A similar step is necessary for installation on

certain revolvers and you must position it very carefully. If

it’s too far forward, it can undermine the strength of the top

strap/recoil shield joint. Too far back and it can interfere

with hammer fall, which at times may require reshaping of

the hammer spur.

You install popular ribs like the Bo-Mar series, with specific

models to fit everything from Colt and Browning autos to S&W

and Ruger revolvers, by accessing existing dovetails. On this

type of job, you need to remove the factory sights, both front

and rear; then, grind off the front blade if it’s an integral

forging. File-fit the rib’s mount dovetail into the slot, taking

care to see that bearing surfaces are in full contact with

lampblack or chalk. With the rib in place, center-punch the

slide or top strap through the rib’s pre-drilled screw holes.

At this point, with the rib still in place, check to see that its

lower contour matches the curvature of the slide or revolver’s

top strap and barrel. If the correct rib fits the particular gun,

it won’t require more than a couple passes with a file here

and there for precise mating. Also check to see that the clear-

ance around the ejection port of an auto loader is sufficient.

If the fit checks out satisfactorily, remove the rib. Then, drill

and tap as previously described. To install, reposition the rib,

then Loc-Tite and tighten the screws (very tight!). Also, stake

the dovetail mount with a punch or (before inserting the

screws) silver solder the dovetail, the bearing surface under

the front sight, or even each pillar on a vent rib when recoil

is especially fierce.

Shotgun Beads

Shotgun beads function in a way that’s unique among all

gun sights. Unlike those found on rifles and pistols, they’re

not intended for any kind of precise aiming. Even when

shooting a gun with more than one bead, there’s no more

34

Gun Sights 35

than a cursory need for alignment. A bead simply signals the

position of the muzzle, without diverting the shooter’s atten-

tion from the target. It serves only as a mid-point reference

in a fluid, reflexive sighting reaction that originates at the

eye and ends with the target. There’s no focusing on the

bead as there is on a front sight; the focus must always be

on the target.

Practically all contemporary shotguns come with a bead at

the muzzle, and a few even provide a second, mid-barrel

bead. It’s the consensus of today’s shotgunners that a bead

helps them get on the target faster, helps determine leads

more clearly, and therefore produces more hits and bagged

game. It’s also true, however, that among all types of gun

sights, shotgun beads are the least critical. This is clearly

seen in the historical use of such beads.

Early Beads on Smoothbores and Flintlocks

Some of the earliest smoothbores, guns dating from 1500s

and 1600s, had small, barleycorn-shaped beads at the muz-

zle. This may lead you to believe that the “shotgun” bead is a

rather old development, but that’s not exactly the case. You

must keep in mind that the traditional smoothbore muskets

most likely shot a single round-ball slug. However, some

shooters observed that they were more effective-at least on

close targets-firing loads made of several smaller projectiles

(buckshot).

Flintlock fowling pieces, long-barreled, large-bore guns that

were the predecessors of true shotguns, were frequently fitted

with a bead or even a low blade. It’s not clear whether this

was a carryover from musket design or if the shooters recog-

nized a need to keep track of muzzles that extended three or

four feet from the eye. But it’s curious that when barrels

were shortened to more conventional lengths on the finer

flintlock shotguns of the early 1800s, beads were few and

ar between.

Throughout the 1800s and into the twentieth century, the

inclusion of beads on shotgun barrels was, at most, occa-

sional. Some guns had them, but many others didn’t. A

prominent rib between side-by-side barrels was often the only

concession to sighting. Where beads really began showing up

Gun Sights

with frequency was on the single-barrel guns (both single-

shots and repeaters) of the early 1900s. Here one can see

muzzle-mounted beads made of brass, ivory, steel (blued

or bright), and eventually plastic. Before long, such beads

became commonplace on side-by-side and over-under ribs

as well. In shape and position, these beads were markedly

similar to those found on the historic muskets. Interestingly,

they remain virtually the same today.

Beads for Today’s Shotguns

While beads remain fundamentally the same as those seen

centuries ago, there’s a healthy selection available for today’s

shotgunners. The choices hinge on three basic variables: color,

head diameter, and shank size/thread. The shooter will also

have to decide if he or she prefers relatively unbreakable

solid metal to more fragile but also more visible enameled or

plastic beads.

The usual colors are white, gold, and orange/red. The blued

steel beads so often supplied by gun makers are rarely cho-

sen for an add-on piece since they’re nowhere near as visible

as the brighter colors. White/ivory beads are either plastic or

enameled, or if solid metal, shaped from bright stainless steel

or aluminum. Gold beads are nearly always brass, but some

may be steel coated with gold-colored enamel. Red/orange

beads almost always contain plastic.

The beads, or globes, can range from .070 inch to .175 inch.

and the smallest sizes are used as a rear bead. The position

of the smallest sizes is normally midway along the rib. The

size one selects for a gun is strictly a matter of personal pref-

erence, since the bead should only act as a reference and

must never draw attention away from the target.

Shank lengths and thread sizes vary somewhat and when

you replace a broken or existing bead, it’s best to stick with

the same size unless the threads have damage. Shanks come

as short as inch and as long as inch. The desired length

will depend on the height of the rib, when present, and barrel

thickness. When the bead is to sit directly on the barrel, a

shorter shank will be in order. Common thread sizes for bead

shanks are 3-56 and 6-48, though Brownells also offers a

number with an 8-40 thread. Additionally, other makers offer

such sizes as 5-40, 6-40, and .146-48 (oversized 6).

36

Gun Sights 37

We should also point out that some manufacturers, Lyman

and Marble among them, offer beads with tapered, unthreaded

shanks driven into place. Also adding variety to the market is

Poly-Choke with a number of arrangements where the bead

is partially enclosed in a compact metal housing. These can

appear as a short cylinder with a rear-facing “lens” or as a

very abbreviated sloping ramp with the bead inset at the

angle of the face and top.

Installing Beads

The majority of bead installations will be screw-in types on

ribbed barrels (Figure 17). If you’re replacing an existing

bead, begin by removing it with a special tool made just for

this purpose. These sight installers have circular jaws that

won’t mar the bead surface even while gripping it very tightly.

(Brownells sells these in three different sizes to match bead

diameters.) Alternately, some beads feature a shoulder that

you can turn with a small wrench (Figure 18).

Beads that won’t screw out with the sight installer you can

cut off flush with a jeweler’s saw. Then, you drill out the

shank left behind and tap the hole for the new installation.

FIGURE 17—Shotgun beads may betapered (left) or threaded (right).

FIGURE 18—A Brownell’s Sight Installer is invalu-able for attachment or removal of screw-on shotgunbeads. It comes in three sizes, with collapsing jawsthat grip the bead firmly without scratching it.

Secure the barrel in a padded vise on the drill press table

using a machinist’s level on the rib to ensure that it’s level.

Set the press to drill no lower than the bottom of the rib. Be

sure to select the correct drill size for the new bead’s thread,

and turn the tap in at least four threads. Using the sight

installer, test the fit, taking great care to start it straight. If

the bead doesn’t seat all the way down on the rib it may be

necessary to grind a little off the shank (again holding it

securely with the bead installer). Apply a drop or two of Loc-

Tite or similar thread cement, and screw the bead in tight.

For the drive-in types, you ream the holes before driving the

beads into place. You can make a jig for this job from a piece

of soft scrap wood in which there’s a hole just smaller than

the bead. Hold the bead in the jig indentation and seat the

bead with a few raps from a light mallet.

You can also install beads on barrels lacking ribs, although

such guns are in the minority today. Such jobs will require

drilling into the barrel. Level up the work with a Top Dead

Center tool, then drill and tap the hole. Run the bead in

snugly and mark the excess shank length, then remove it

and, with a jeweler’s saw, cut off that part that penetrates

the bore. With a file or a small grindstone in a Dremel tool,

gently hone the stud flush after final screw-in. Polish over

the joint and any filing marks with a polishing point or emery

paper (Figure 19).

Gun Sights38

FIGURE 19—Shown on the right is a finished bead installation on a double-barrel shotgun. On the left is a cutawayview of the installed bead. (Photos courtesy of U.S. Repeating Arms)

Gun Sights 39

Self-Check 2

Fill in the blanks in the following statements.

1. _______ _______ aren’t meant to be carefully aligned on a moving target.

2. Originally, glow-in-the-dark sights were developed for _______ and _______ use.

3. When mounting a screw-in bead, it helps to use a _______-jawed sight installer.

4. Because they aid visibility in dim light, police and hunters have found it useful to outfittheir handgun sights with _______, _______, or _______.

5. The three basic variables of replacement shotgun beads are _______, _______, and_______.

6. Sight alignment is crucial to handgunners because the _____ sight radius magnifieserrors.

7. Low-profile _______ sights for semiautomatics cannot be simply screwed or soldered in place.

8. Top-quality rear pistol sights are adjustable for _______ and _______.

9. You can usually fashion the slot for a new front sight blade with a _______ and needlefiles.

10. The popular Patridge-style sight combines a _______ rear notch and a flat-sided post.

Check your answers with those on page 97.

SCOPES: A BETTER LOOK

Since World War II, no development in the shooting world

has been more important than the adoption of scope sights.

These gun-mounted telescopes have garnered near universal

acceptance for the simple reason that they help shooters

achieve greater accuracy-more targets hit, more game

bagged. The shooter achieves accuracy in a number of ways.

• The shooter can see the target better.

• The shooter can fine-tune his or her aim by picking out

a spot on the target, or a vital area on game.

• The sight rarely obscures the target.

• As modern scopes developed, sight picture acquisition

became faster to the point where many shooters can “get

on” the target or game animal faster than by aligning

iron sights.

As a result of scope sights, older shooters have had their

sporting years extended and hunters are vastly more efficient

in the critical dawn and dusk periods. Also, those who are

unable to spend a lot of time practicing find it somewhat

easier to develop marksmanship skill.

Scopes aren’t without drawbacks, however. They add weight

to the gun and even the improved current models can’t

always stand up to rough handling. When something goes

wrong “inside,” you can’t repair the scope at the range or in

the field. Unless you can employ an alternate sight, the gun

is effectively out of commission.

Fortunately for today’s hunters and shooters, the reputable

scopes on the market aren’t prone to failure if treated with

reasonable care.

History and Development

We’re not certain who first mounted a telescope on a rifle.

However, the first occurrence of a scoped rifle probably came

shortly after the seventeenth-century German astronomer,

Johannes Kepler, improved on earlier telescope concepts.

Gun Sights40

Gun Sights 41

Kepler managed to reproduce an image within the tube

rather than relaying it to a “focal point” somewhere behind

the rear lens.

Kepler’s innovation required changing the curvature of the

front or objective lens to bring light rays together at an inte-

rior focal point. The rear or ocular lens was ground to focus

on the image and thus relay it to the eye. Kepler’s efforts

resulted in a much truer image delivered by a glass of man-

ageable size. (In attempts to get the lenses to focus, early

telescopes were often yards long.) Even with Kepler’s

improvement, images were usually fuzzy and distorted,

and to the viewer they appeared upside-down. One can

only imagine how fragile and prone to fogging these telescopes

were, so it’s understandable why they weren’t exactly an

immediate hit with shooters.

The performance of scopes improved as optical discoveries

occurred. Compound lenses, fashioned from two affixed

pieces of glass with differing optical properties, greatly

reduced troubling distortion. It was found that an erector

lens, inserted inside the tube between the objective and ocu-

lar, would set the image back on its feet. By the early 1800s,

gunsmiths and glass makers teamed up to build workable

telescopic rifle sights. By mid-century, American target

shooters used scopes, and Civil War snipers put them to

effective, if limited, use.

Over the next 50 years, scope sights were being crafted in

various places, and their availability was fairly widespread.

However, the hunting and shooting public still didn’t rush to

embrace their development. These scopes, many of which

were nearly a yard long and built around heavy-gauge steel

tubes, could add three to five pounds to an already ponderous

Sharps or Springfield rifle.

The long tubes and their nineteenth-century lenses seemed

to trap more light than they transmitted. Shooters likened

looking through one to being deep in a tunnel. The glass was

quick to fog in bad weather, and obtaining and maintaining a

positive aiming zero was, at best, trying. Shooters still found

iron sights most reliable for fighting Indians, for hunting, and

for protecting a frontier homestead.

The turning point came about the turn of the century when

scope lengths shrunk to under a foot and a half. Though

they still lent themselves well to bright-light situations, this

new breed of scopes caught on with target shooters first,

and hunters to a lesser extent. American firearms firms

like Stevens and Winchester, along with the German optics

makers Zeiss and Hensoldt, began mass-producing the

instruments. Not coincidentally, this was the dawn of the bolt-

action rifle era, and these two technological breakthroughs

seem to have augmented each other’s development. With bolt

rifles, shooters achieved much more accuracy than was pre-

viously possible. To take advantage of it they needed better

sights, and scopes provided this higher level of precision.

Refinements in the 1930s made scope sights even more pop-

ular and versatile, and while many shooters remained skepti-

cal about their usefulness, scopes spread to rifle ranges and

hunting camps across North America. Continued down-sizing

spurred the introductions of models like the Lyman Alaskan

and Weaver 330. Such scopes were about a foot long, built

on slender 3/4 or 7/8 inch tubes, and came in relatively low

2.5X and 3X magnifications respectively. These lightweight

scopes had great appeal to hunters.

By the decade’s end, Zeiss had developed a process to treat

lens surfaces with a thin, transparent layer of fluoride or

magnesium oxide. This was a giant step toward eliminating

the traditional problem of light reflecting from the glass

rather than passing through it (Figure 20).

Coated lenses are far more efficient at transmitting the light

they take in, therefore conveying brighter, clearer images,

even at times of dim ambient light.

The years following World War II brought a series of further

refinements that finally won the shooting public’s favor. One

major refinement involved filling the tube with nitrogen gas

and sealing it airtight. This prevented fogging of the inner

lens surfaces when the shooter encountered temperature

extremes or wet, humid weather.

The early 1950s saw the advent of variable scopes that could

increase or decrease magnification power at the turn of a

ring. Shooters soon learned that scopes could be highly ver-

satile-at least with the resolution of the problems of reticle

Gun Sights42

Gun Sights 43

“growth,” inferior light-gathering and field of view, and zero

shifts. Current variables are nearly the equal of fixed-power

models in most regards. They’re perhaps a bit bulkier, but

they’re capable in more situations.

Reticle presentation then became upgraded. The aiming

marks, seen as crosshairs, posts, dots, and various other

combinations came to be made of fine wire or filament and

lines etched on glass. In years past, they looked like spider

webs. They come in various widths, arrangements, and

combinations, depending on the design (Figure 21).

FIGURE 20—The latest line of Carl Zeiss scopes, the Z-series, features the patented Zeiss T multicoating, whichevolved from Zeiss’ early work with lens coating. (Photo courtesy Carl Zeiss Optical, Inc., Petersburg, VA)

In most older scopes, the reticle was permanently fixed within

the tube. The only way to make a sighting adjustment was

to move the entire scope in its mount. Early scope users

considered an external adjustment superior (even though

it required a bulky, delicate mount) because it allowed the

scope’s construction to be simpler, stronger, and more

effectively waterproof (Figure 22).

A few older models featured reticle adjustment inside the

tube (usually just one), and the reticles tended to move off-

center in the field of view. Today’s models feature permanent-

ly centered reticles, easily adjusted by screw-in or dial mech-

anisms housed in the upraised turrets located midway along

the scope body. You would rarely see external adjustment

Gun Sights44

FIGURE 21—Here are the most common scope reticle styles (from left): crosshairs, post,duplex, and dot.

FIGURE 22—You’ll find exter-nal adjustment scope mountsonly on match rifles thesedays, as advancements inoptics technology have led to internal adjustments thatare both accurate and reliable.Nevertheless, competitorsremain loyal to large-knobbedmicrometer fixtures that movethe scope body from the outside.

Gun Sights 45

scopes any longer outside bulls-eye competition or on collec-

tor guns; and in the United States, only Unertl still makes

this type scope and mount. Instead, we now see multiple

crosshairs, range-finding scales, and battery power for illu-

mination in the dark.

After nearly 200 years of development, today’s scopes provide

tremendously effective sights for millions of shooters. They’re

strong, lightweight, and reliable, and by making the targets

appear larger, brighter, and sharper, they make us better

shooters and hunters.

Functions and Features of Rifle Scopes

The great demand for scopes by nearly all segments of the

hunting/ shooting world has spurred the evolution of a wide

range of highly specialized models. Today you can buy scopes

specifically designed for hunting anything from a rat to a

grizzly bear, for pinpointing tiny X-rings or distant steel sil-

houettes, or just for knocking tin cans off a fence post. There

are scope sights made for pistols and shotguns. There are

also others intended solely for air rifles, and amazing night

vision units (not widely available to the public) for military

and police sniper duty. Also available are infrared rifle scopes

for hunting that maximize light transmission in the red part

of the color spectrum.

By far, the most common scopes are hunting rifle scopes, but

even these come in a mind-boggling array of shapes, sizes,

power capabilities, and internal features. Most likely the con-

ditions of the hunt or competition or recreational pastime will

determine the appropriate model (Figure 23).

Hunting Scopes

Hunting scopes must go beyond simply presenting a clear,

magnified picture of the intended quarry. Big game hunters

can often benefit from the scope’s enhanced twilight capability,

a function achieved by employing a large-diameter objective

lens that takes in lots of light (Figure 24).

Gun Sights46

FIGURE 23—Pictured are Steiner’s revolutionary new color-discriminating rifle scopes. The Penetrator series maximize light transmission in the red part of the spectrum, reflect blue and green light back into the woods, and enhance the eye’s ability to spot game against a forest background. (Photo courtesy Steiner Optik through

Pioneer Marketing & Research, Inc., Westmont, NJ)

Gun Sights 47

Variables

Objective lens diameter isn’t the only element that con-

tributes to overall size. There are other dimensional factors to

consider when selecting a scope. Variables, because they

must accommodate shifting interior lenses, are nearly always

longer than similar fixed-power models. The wider the range

of power settings, the greater the length required. For exam-

ple, a 6-24X scope will be considerably longer than a 3-9X of

similar optical quality. The greater length also adds weight

and makes the scope more likely to snag on or bump against

brush.

An additional size consideration is the scope’s proportion to

the rifle. On a diminutive .22, a carbine, or one of the new

breed of down-sized “mountain” rifles, a massive, large-objec-

tive variable will disrupt the balance. This makes for a top-

heavy unit that comes to the shoulder clumsily and is slow

to access the target. Also, the looks of such a combo will be

just as awkward to many. Generally, a smaller-sized rifle will

handle and look better with an optic built on a similar scale.

FIGURE 24—Pictured is the Leupold 3 ö 9-50mm large objective variable scope that provides hunters with maxi-mum visibility during early morning and late evening hunts. Those who will be walking far or climbing mountainswill suffer, however, from the extra weight of a “wide-eyed” model. These users probably will want to compromisefor a more compact unit that combines reasonable twilight ability with a handy carrying weight. (Photo courtesy

Leupold & Stevens, Inc., Beaverton, OR)

Various Power Ratings and Their Uses

Perhaps the key factor for most scope purchasers is power

rating, an area where an enormous range exists. Today you

can find scopes ranging from 1X (no magnification) all the

way up to 40X (or greater in customized models). You must

understand that as power increases, field of view decreases.

For example, a typical 4X scope will deliver a 32 foot width

of field at 100 yards, while a 10X shows only 12 feet at that

distance. This varies somewhat with construction but not

greatly, and variables nearly always yield a smaller field at

the same power as fixed scopes.

Shooters who can genuinely use higher magnification scopes

are probably firing on stationary targets easily distinguished

from their background. This would include bulls-eye, silhou-

ette, and bench rest competition, varmint hunters, and to

some extent, stalking big game in open plains country.

For use on game that’s moving and/or in heavily wooded or

brushy areas, a high-powered optic with its very limited field

of view frustrates hunters’ ability to engage and hold on their

target.

For hunting most North American big game-deer, elk, black

bear, and moose-big game hunters have settled on 4X as the

consensus setting. Today, the 3-9X variable also enjoys great

popularity. Such scopes offer a good field of view, are normally

fitted with a 32mm or larger objective for optimum light gath-

ering, yet aren’t overly large, weighing anywhere from 10 to 15

ounces. At 4X, deer-sized or larger game is sufficiently mag-

nified for the shooter to attain lethal shot placement at the

practical limit of his or her ability to shoot accurately-out to

300-400 yards.

Many professional guides opt for iron sights on their “stop-

ping” rifles when hunting grizzly bears and dangerous game

in Africa. Their scopes are usually at the low end of the

power curve, 1X to 3X, as field of view and speed become

more important than increased magnification. Objective lens

sizes are also scaled down on such scopes, since the hunters

prefer economy weight (under 10 ounces) and maneuverabili-

ty to twilight capability. We should make clear here that

objective lens dimension has nothing to do with field of view.

Gun Sights48

Gun Sights 49

Rather, the ocular lens governs the visible field. Generally,

lenses that yield wider fields require diminished eye relief

(the distance from the rear lens to the eye), so a compromise

must be made here to make the scope functional.

Hunters can use higher-power scopes like 6X to 12X to great

advantage for open-country game like pronghorn and cari-

bou. Here, long shots are the rule and the hunter can often

take the time to get in a steady shooting position. Objectives

tend to be big on such scopes (40mm or more). However, if

the hunt involves much walking, the 12 to 20 ounces they

can add may prove burdensome, and again, the user is bet-

ter off with a smaller model.

Those who climb for bighorn sheep and mountain goats,

usually found in fairly open places where a close approach is

unlikely and shots tend to be long, also need the smaller

model. Reaching sheep and goats is such an arduous ordeal,

however, that hunters look for any possible way to lighten

their loads. Sheep and goat hunters often rely on 3X to 6X

scopes or smaller variables with mid-size objectives. Ideal

for such hunting (and also finding favor for use on antlered

animals) is a new class of low-end variables, a 1.5-6X, 2-7X,

and 2.5-8X category. They offer surprisingly good definition

and light-gathering ability despite streamlined objectives that

may measure no more than 20-28mm.

Among hunters, varmint hunters are most likely to use heavy

powerhouse scopes. These formidable optics often range up

to 20X or 24X, and at times exceed 30X, although, at that

magnification, the mirage of heated air rising from the

ground can be thoroughly distracting. Needless to say, the

quality models offer tremendous magnification. The magnifi-

cation makes it possible for a flat-shooting, heavy-barreled

varmint rifle to hit a tiny target as far as a quarter mile

away. Weight isn’t such an important factor here since the

sport typically involves very little walking and the shooters

fire from a rest or otherwise supported position.

Varmint scopes are likely to boast huge objective lenses,

from 40 to more than 50mm. This isn’t because the users are

expecting to encounter game at the very beginning and end

of the day in the manner of deer hunters. Rather, the higher

power requires a greater amount of light to transmit a high

degree of clarity and resolution. Related to this is the peren-

nial question concerning the optimum power setting in low

light. Many shooters believe that lower powers are superior at

these times because they do a better job of transmitting light.

However, higher magnifications are actually better at aiding

visibility simply because they bring the image closer. Compared

to what one sees with the naked eye at 150 yards, an image

at 4X appears to be inside 40 yards. But at 8X that same

subject looks as if it’s just 20 yards away (Figure 25).

Another feature found on most varmint scopes that may be

missing from other hunting models is parallax correction.

Parallax is an image transmission condition that can lead

to sighting errors when the focal point doesn’t coincide with

the plane occupied by the reticle. That is, the image projects

ahead of or behind the reticle. You can notice this condition

when the subject seems to “float” over the reticle as the

user’s head shifts. When parallax isn’t present, the image

and reticle move together. Parallax becomes pronounced only

on very close images, say inside 50 yards, and at that range

the sighting error is insignificant on all but the smallest tar-

gets. Beyond 150 yards, very little parallax will be evident.

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FIGURE 25—Shown is the Leupold 3.5 �� 10 adjustable objective varmint scope. Its distinguishing feature is aunique elevation adjustment system borrowed from Leupold’s legendary bench rest scopes. The shooter can makeadjustments in 1/4 minute intervals, enabling him or her to “pinpoint” shot placement, which is what varminthunting is all about. (Photo courtesy of Leupold & Stevens, Inc., Beaverton, OR)

Gun Sights 51

Most modern scopes are manufactured to be free of parallax

at 150 yards. Because some varmints present such minus-

cule targets and because parallax is much more noticeable at

higher powers, manufacturers have outfitted certain scopes

with adjustable objective lenses. These lenses simply rotate

one way or another according to marked gradations to cor-

rect for a particular distance. Most target scopes will also

have this feature, as do certain lower-power models more

typically suited for big game hunting. The parallax correction

may not have much practical application on these, but it

does offer a bonus for shooters concerned with ultimate

accuracy. For serious varmint hunters, however, parallax

correction can produce tangible results in the field (Figure 26).

Hunters of small game like squirrels and rabbits, as well as

plinkers, can usually satisfy their needs with small (4 to 8

ounces) low-magnification scopes. These are often built on3/4 inch tubes, housing objective lenses with 15 to 24mm

diameters, and they rarely exceed 4X. Intended for .22 rimfire

rifles, these low-end scopes provide adequate magnification

and light-gathering ability for the short ranges over which

the guns are effective.

FIGURE 26—Parallax is a condition that occurs in optical sighting instruments when the image is transmittedbehind (middle figure) or in front of (lower) the reticle. Error-free sighting occurs only when the scope is free ofparallax (top), though the degree is usually insignificant unless targets are quite small, in which case the shooterwould use a higher-powered scope.

Target shooters need not consider quite so many variables

when it comes to selecting a scope. When the emphasis is on

precision, and shooters line up their shots with painstaking

effort (as is the norm in most competitive shooting) magnifi-

cation is a vital factor. Therefore, bench rest, bulls-eye, and

silhouette match shooters want and can use plenty of power

without suffering from the resulting weight and narrow field

of view. 15X is about the minimum commonly employed by

experienced marksmen and it’s not unusual for top competi-

tors to resort to scopes topping 30X and even 40X.

We should note that everyone can’t use such extreme powers

effectively. While it’s true that the target will appear much

larger, it’s also true that the shooter’s movements are equally

magnified. Unless the shooter fires the rifle from a supported

position, as is the case in prone or bench rest events, it will

seem that the target is “dancing” across the field of view. It

takes a skilled rifleman with supreme powers of concentration

to steady this sight picture and make a good shot. The lack

of time to accomplish this is another reason why big game

hunters are unable to benefit from ultrahigh-power optics.

Quick and precise sighting adjustments are also important

to competitors. Because subtle shifts in the wind can cost

points, shooters must be able to make instant corrections.

On scopes designed for silhouette and bench rest shooting,

high-profile adjustment knobs shift the cross-hairs slightly

with each readily felt “click” (normally inch at 100 yards).

Silhouette shooters also use this system when moving from

one target distance to another, dialing a predetermined num-

ber of clicks to alter points of impact.

In bulls-eye shooting, shooters encounter the last vestiges

of external adjustment in the form of micrometer-style rear

mounts. Supporting 20X to 25X, long-tube scopes with fixed

reticles, these precision mounts contain spring-loaded stabi-

lizers that press opposite the two graduated micrometer

heads, one for elevation, the other for windage. As with scope

turret knobs, they work with audible and felt clicks. There are

usually 50 clicks per revolution of the head and the distance

each click shifts the point of aim depends on the measurement

between the front and rear bases. The closer the mounts, the

greater the adjustment. Smallbore rifle shooters, who typically

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Gun Sights 53

want 1/4 inch clicks at 50 yards, accordingly will space front

and rear mounts 7.2 inches apart.

Pistol, Shotgun, and Air Gun Scopes

Though some once considered it odd, it’s no longer unusual

to see a scope mounted on a pistol, shotgun, or air gun.

Recent scope designs and materials have made it possible

to attach a scope to virtually any type firearm.

Pistol Scopes

Pistol (or handgun) scopes emerged as a major development

of the 1980s with models tailored specifically for hunting and

competition, for revolvers, semiautomatics, and single-shot

guns. When employed by skillful handgun shooters, they

yield the same benefits enjoyed by rifle shooters for so many

years.

The obvious restrictions on size/weight (7 to 10 inches and

about 8 ounces is average) and the pistol’s relatively short

effective range have limited useful features, however. Low

magnification (typically 1X to 4X and rarely topping 6X),

compact dimensions, and moderate light-gathering capabili-

ties characterize today’s pistol scopes. In addition, eye relief

is a critical factor. For many years this was also the case

with rifle scopes. The shooter had to hold his or her head

rigidly in just the right position to see the full field of view.

The tendency was to creep forward on the stock and end up

with a half-moon cut on the forehead from recoil (Figure 27).

Design advancements have given shooters a couple inches

leeway in obtaining proper eye relief, an especially important

concern of hunters who must get “into” the scope

and “on” their targets in a hurry. And in certain

cases shooters will also opt for long eye relief, when

fierce magnum recoil is present or on rifles where

the scope is mounted in a forward position.

FIGURE 27—Eye relief is the distance between the scopeocular (rear) lens and the shooter’s eye. You mustaccount for eye relief when mounting the scope. Eye relief varies from one individual to another, so the shootershould be on hand for measurement.

Eye relief for a pistol scope user is a more demanding propo-

sition since shooters hold handguns some distance away

from their head and because there’s no cheekpiece to estab-

lish a natural line of sight. Pistol scopes are built so that the

correct eye relief will appear about 10 to 20 inches behind

the ocular lens. It takes a good deal of experience to be able

to routinely assume and maintain this position (Figure 28).

Hunters and silhouette shooters will generally opt for more

powerful 3X and 4X models with larger objective lenses

(though normally not larger than 32mm). Bulls-eye and

practical competitors who perform in rapid-fire events

that demand speed tend to stick to lower 1X, 2X, and 3X

magnifications.

Electronic optics are also quite popular with match shooters,

particularly among bulls-eye competitors. These units operate

on small batteries and project an illuminated dot onto the

field of view (Figure 29).

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FIGURE 28—Handgun scopesprovide extended eye relief,that is, greater distancebetween the eye and rear lenswhile still providing a full fieldof view. Lower magnifications,like 1.5X to 3X, are the mostpopular, but higher powers areavailable.

Gun Sights 55

The dot acts as a reticle and you can adjust the width and

intensity by turning a switch. Electronic optics caught on big

in the early 1980s because they’re fast to acquire the target

and offer a somewhat simplified sighting procedure. More

importantly, they have prolonged the competitive careers of

many older shooters who began to have trouble focusing on

their front sights. Originally, electronic optics were without

magnification, but recently we’ve seen the production of 2X

and 3X models. Handgun hunters haven’t been so quick to

adopt the electronics, probably due to the electronics’ bulk

and lack of useful magnification. On rare occasions a shooter

may want an electronic sight mounted on a rifle or shotgun

(Figure 30).

FIGURE 29—The Aimpoint5000 is a 30mm electronicred dot optical sight that runson lithium batteries. The mainunit, designed for all types ofpistols and revolvers, meas-ures 5.5 inches. It’s not nec-essary to focus or center thedot. The shooter simply putsthe dot on the target andshoots. (Photo courtesy of

Aimpoint, Herndon, VA)

FIGURE 30—The compactlightweight Laserdot utilizes astate-of-the-art laser diodethat eliminates all movingparts and tubes, which werenecessary in earlier designedlasers. This allows theLaserdot to withstand heavyrecoil and demanding shootingconditions. Laserdot mountseasily into standard one inchrings, or with its optional railmount for use on pistols,rifles, shotguns, air rifles,and bows. (Photo courtesy of

Aimpoint, Herndon, VA)

Shotgun Scopes

Just as handgun optics became quite common in the preced-

ing decade, scopes for both regular shotguns and those

bearing slug barrels will become widespread in the 1990s.

Fast-developing areas restrict rifle use for deer hunting. So

more and more hunters will have to turn to shotguns if they

want to continue the sport (Figure 31).

Shooters have experimented with shotgun scopes (often suc-

cessfully) for many years, but recent improvements in slug

barrels and slugs made these guns accurate enough to bene-

fit from precision sights. The majority of shotgun scopes on

the market are lightweight, low-magnification models of 4X

or less with objectives around the standard 32mm. Expect to

see this category grow over the next several years (Figure 32).

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FIGURE 31-The Leupold 1 �� 4 shotgun scope is just one in a line being designed specifically for shotgun hunters.Leupold shotgun scopes are parallax-adjusted to deliver precise focusing at 75 yards, as opposed to the 150yards, which is typical of rifle scopes. (Photo courtesy Leupold & Stevens, Inc., Beaverton, OR)

Gun Sights 57

Air Gun Scopes

Scopes that carved out a steady market niche are those

designed specifically for air guns. Along with the development

of pellet rifles and pistols powerful enough to kill pests and

small game came the demand for suitable optics. At first

some felt that air gun scopes would work well on any small

firearms model, but they did not hold up on hard-recoiling

spring-piston guns. Lenses would crack, reticles would shake

loose from their moorings, and internal adjustment mecha-

nisms would go haywire.

The problem was caused by the way these scopes were

designed to withstand the rearward thrust of firearms recoil.

The spring-piston gun acts in exactly the opposite manner,

kicking forward when the piston slams against the front of

its cylinder.

Air arms manufacturers and importers soon introduced

scopes with lenses braced to withstand forward recoil and

enthusiasts rushed to put them on their guns.

Air gun scopes have been modest in size and power, commonly

4X with 32mm or smaller objectives. However, a number of

variables up to 3-9X and 4-12X with 40 to 50mm objectives

have also been on the market. A feature many of them have

included is manual parallax correction, necessary for the

close ranges and tiny targets. Air gun silhouette and field

target events are growing sports, but recent technology in

compressed air power has led to light-recoiling guns that

don’t need specially braced optics. Also, many higher-quality

firearms scopes already have the rigid construction to stand

up to spring-piston recoil.

FIGURE 32—In 1989, Remington introduced a complete rifled slug accuracy system for its 12 gauge Model 11-87semiautomatic and Model 870 pump-action Deer Guns. They feature a permanent, integral scope mount on thebarrel and a new, interchangeable, rifled “Rem choke” tube. They also have a permanently attached cantileverscope mount, including rings, that extends back over the receiver to provide normal eye relief with rifle scopes.(Photo courtesy Remington Arms Company, Wilmington, DE)

Reticles

When deciding which scope to buy, the purchaser must also

consider the type of reticle that suits his/her needs. As previ-

ously mentioned, they come in three categories: crosshairs,

posts, and dots. Within each category there’s a mind-boggling

number of variations.

Crosshairs

Fine crosshairs are excellent for precise accuracy but they

can be difficult to see in poor light. Bulls-eye target competi-

tors who have the time to “find” them and some varmint

hunters favor them.

Posts

Posts are especially popular in Europe where they originated.

They come in single (one vertical from the bottom), three-post

(from the bottom and sides), and four-post (all four directions)

versions, usually ending in a point. They don’t meet, therefore

leaving a clear area in the center of the field of view. Post ret-

icles are easy to see and don’t obscure the target, but don’t

facilitate finely tuned aiming. They’re very useful for big game

at close ranges.

Duplex

A combination of the post and crosshair styles is the duplex

reticle. The duplex’s “legs” begin as thick posts, then taper

abruptly to narrow crosshairs at the center. Frequently they

are without a top post. The solid posts provide an easily

accessed reference and the thin central hairs allow fine preci-

sion, so long as the light is sufficient to see them. Even when

conditions are rather dark, the post arrangement makes it

possible to use the scope with satisfactory results. Duplexes

are probably the most versatile reticles, and are quite popular

among U.S. big game hunters.

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Dots

Dot reticles lend themselves well to the specialized uses of

match and varmint shooting. In such uses the shooter has the

time to pick up a circular point small enough to provide exact

aiming without obscuring the target. Top competitors often

find it easier to concentrate on a dot during lengthy events,

especially in the standing position when the pronounced

movement of crosshairs can be a nagging distraction.

Bulls-eye shooters use one-minute-of-angle dots that match

the size of their X-rings, whereas bench rest shooters want

pinpoints as tiny as one-eighth minute. Varmint hunters

sometimes experiment with multiple dots on a vertical axis.

Installed by custom scopesmiths, they show point-blank

holds for various ranges with a given load, or are made

in different sizes to indicate range on a certain animal.

Obviously, it takes a knowledgeable, accomplished shooter

to realize their potential.

At the risk of digression, it is important to note that you can

make range estimates by using a system of parallel horizon-

tal crosswires designed to bracket a certain measurement at

a specified distance. Often this measurement is 18 inches, the

nominal depth of a mature deer’s chest. The user determines

the distance to the animal by trying the various brackets,

then uses the appropriate crosswire for the hold. This takes

time, of course, and at the moment of truth such systems

with their numerous wires often prove confusing. Not many

big game hunters opt for such range-finding scopes.

Mounting a New Scope

Although mounting a scope on a rifle isn’t a difficult gun-

smithing task, you must do it correctly for the rifle to perform

to any standard of accuracy and consistency. A gun with a

crooked, loose, or otherwise improperly mounted scope sight

simply won’t shoot straight. For that reason, many gun owners

prefer to have a professional accomplish this important task,

relying on his/her expertise to get it done right-regardless of

the added expense.

For the gunsmith, scope mounting is a measure of profes-

sional service that involves customer relations as much as

technical know-how. The amount of time it takes to install

a scope on most modern hunting rifles is minimal, since

they’ve been manufactured with the presumption that a

scope will eventually be mounted. Older guns, military

weapons, and certain target models may pose more of a

challenge, although mounting hardware is commercially

available for practically any modern mass-produced firearm.

A professional scope-mounting job should be a confidence

builder for the customer. It is the finishing touch on any

gunsmithing operation that requires disassembly of the gun,

the cap to the purchase of a new firearm, or perhaps new

“eyes” for an old friend. With the scope properly mounted,

the shooter heads to the range fully confident in his/her

equipment.

Mount Components

Mounting a scope on a gun requires using hardware made

specifically for that gun. Hardware usually includes mount

bases (or blocks) and rings (Figure 33).

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FIGURE 33—Leupold’s basesand rings are now available inmatte (sheenless) finish.(Photo courtesy Leupold &

Stevens, Inc., Beaverton, OR)

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You’ll find some of the hardware fashioned as one-piece

combination base/rings. In some cases, the firearm will have

parallel dovetail grooves machined into the top of its receiver,

and these you can use for attaching simple clamp-type rings.

Rifle Mounts

On nearly all rifles, mount bases join directly to the receiver

or side plate with screws. This is a straightforward job on

most guns since they come from the factory with screw holes

already tapped. There are a number of manufacturers offering

quality mounts tailored for an extensive selection of modern

rifles, and it’s not difficult to find mounts for many older

models. Many such bases are sold in kits containing the

correct screws.

The rings hold the scope. These come in 3/4, 7/8, and 1 inch

sizes, as well as metric 26 and 30mm diameters. One inch

rings are by far the most prevalent. Most rings consist of

mated semicircles that detach to accept the scope, then re-

attach with screws. Formerly, rings were also circular bands

that cinched tight at an overlapping union. These were fine

for accommodating straight-tube scopes (those lacking flared

ocular and objective bells) but bending them wide enough to

fit around the tube sometimes caused them to crease or to

scratch the scope. You’ll find split rings used in almost all of

the current mount offerings.

Rings attach to mount bases in several ways as follows.

• Some clamp to the mount’s rail or rib-like features

• Others hold onto a slot with a spreading claw

• Another type fits over a protruding stud and is held in

place by friction or with a set screw

• Still others screw directly to holes threaded in the base

All of these methods have proven effective so long as the

device is well made of quality materials, but logic suggests

that the simplest design with the fewest parts will be the

strongest.

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Mount bases and rings were originally made of steel and

most still are. However, aluminum mounting hardware is

catching on quickly as a lightweight alternative, and in most

cases is proving sufficiently durable.

Among the numerous scope mounts introduced over the

years, a handful stand out as enduring and popular. The

best ones have proven durable, easy to install, fairly light-

weight, and able to maintain the scope’s zero when refitted

after removal. You can scope virtually any rifle from the

smokeless powder era except for certain later military arms.

One of the most popular types of “top” mounts-so-called for

its position on top of the receiver or barrel-is the dovetail

style. Generally, dovetail mounts come as rails that attach to

the receiver with screws, or on small-caliber rifles, grooves

milled into the receiver. The rail, which comes in both one-

and two-piece configurations, is beveled top to bottom to mate

with corresponding clamping “jaws” on the rings’ riser piece.

Most frequently the dovetail rail screws into tapped holes on

the top of the receiver, particularly on a bolt-action rifle.

You’ll often find a side plate mount used in the case of lever-

actions like the Model 94 Winchester, where the rear of the

receiver pivots back to open the breech. As the name sug-

gests, the side plate style of mount fastens onto the receiver

wall via screw or pin holes. The plate extends upward along

the receiver to suspend the scope above the bore axis, either

angling into position directly over the top of it, or holding it

out to one side (diagonally to the bore) on top-ejecting actions

such as the older Model 94s. Many side plate mounts also

incorporate some type of dovetail grooves, thereby enabling

use of the most common-type ring.

Around 1950, the W. R. Weaver scope company of El Paso,

TX, introduced what has probably been the top-selling mount

of all time. The Weaver top mount is a dovetail rail improved

by a perpendicular slot that engages long ring-clamping

screws. The design acts as a recoil lug for the scope and it

provides a much greater bearing surface than the clamp ears

alone. Weaver-type mounts fit a long list of rifle models and

many manufacturers offer rings to fit it. The Weaver-type

mount has gone through minor changes (notably in the

clamping screw) but this proven mount remains a favorite of

American shooters and currently fits hundreds of rifles.

62

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Another old favorite is the Redfield-style mount, still made by

that company and many others. It’s available in one- or two-

piece versions, the bases secure the front and rear rings in

different ways. The front ring has a circular, dovetailed stud

on the bottom, which you insert into the base, then turn to

lock in place as it snugs against the oblong base slot. The

rear ring is snugged by countersunk screws on either side.

The Redfield type and similar designs make scope removal

quite fast, as it’s only a matter of loosening the rear ring,

then pivoting the works free of the front base (Figure 34).

Many big game hunters favor quick-detachable scope mounts

though they’re the most expensive on the market. Such

mounts facilitate rapid scope removal/replacement with rings

featuring lever or claw-like fixtures that clamp onto the base

with simple hand manipulation. Many, though not all, of the

quick-detachables are European made. Their built-in clamp-

ing mechanism boosts their price.

Pistol Mounts

Pistol mounts function much the same as those for rifles,

at least in the case of revolvers and single-shots, where the

bases respectively fasten onto the top strap or barreled

action. Most handgun mounts can utilize adjustable sight

screw holes. If they’re not present, you must drill the holes

accordingly. Also, there are quite a few “no-gunsmithing”

versions that clamp onto the top strap or another part of

the frame in addition to using any existing screw holes.

FIGURE 34—The Redfieldbridge-type mount has beenaround for more than 50 yearsand is still going strong. Itspopularity is in part due to itseasy-off/easy-on again capa-bility. This is made possible by turning the rotary dovetailstud on the front ring into asnug friction fit in an oblongslot on the base.

There may also be a ring-like brace that clamps directly

around the barrel for installing the mount on a hard-recoiling

magnum revolver. These guns often have three rings to

secure the scope in the wake of the violent recoil. Generally,

“no-gunsmithing” mounts simplify the installation job, but

also add significant bulk to the gun.

Scope mounts for a semiautomatic pistol are often more elab-

orate than on a revolver since the slide must remain free to

move back and forth. Again, frame-clamping versions are

available, but many shooters who want to scope self-loaders

choose grip mounts. These have a long extension that angles

down on the side opposite the ejection port and replaces the

factory grip. Accordingly, this portion of the mount is shaped,

checkered, and/or finished to match the standard grip. It

features screw holes that line up with those in the frame,

making for a handy installation job (Figure 35).

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FIGURE 35—The “Guide-Line” handgun scope mounts from Williams eliminate installation problems often encoun-tered when installing a scope on a handgun. They install easily with no required drilling or tapping. (Courtesy

Williams Gun Sight Company, Davison, MI)

Gun Sights 65

Slug Shotgun Mounts

Many of the latest slug shotguns are factory drilled and tapped

to accept top mounts just like a rifle, but most existing slug

bores must be customized for this purpose. Additionally,

there are side mounts expressly made for certain models;

some require gunsmithing, some attach by replacing factory

trigger pins with long mount bolts, and others simply clamp

to the receiver. Redfield makes a mount that clamps onto the

rib, making it possible to scope side-by-sides and over-unders

as well as the more customary pumps and semiautos.

Scope Installation

There was a time when the most difficult part of mounting

a new scope was correctly aligning it with the gun’s bore.

This required a professional gunsmith (or at the very least a

knowledgeable enthusiast) using try squares or a drilling jig

to determine true mount placement. Today the guns come

drilled and tapped from the factory, which all but eliminates

the preliminary step. Even if they weren’t, or in those rare

instances where the screw holes aren’t true, modern scopes

have a much greater capacity for adjustment than their pred-

ecessors-certainly enough to compensate for minor misalign-

ment. When you can see misalignment, however, you should

return the gun to the dealer or manufacturer. In instances

where you can’t return the gun, it may be necessary to drill

new mount screw holes. Then it will again be crucial to

achieve proper alignment with the bore.

For the majority of scope-mounting jobs today, the first step

is to thoroughly cleaning any grease or oil from the gun,

mount, screws, and the scope itself. Residual lubricant on

any of these parts can lead to future slippage. Even the

slightest movement can undermine accuracy, causing the

scope to shift within the rings, perhaps damaging the tube

or adjustment turrets. Even worse, recoil applied to a loose

mount can sometimes shear off screws, and the entire works

may jerk free of the gun.

Wiping with a clean cloth will probably do, but to ensure

clean mounting, you should use a fast-drying solvent or

degreaser. Don’t forget to include screw threads and screw

holes, which you can access with cotton swabs (Figure 36).

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Attaching the Mount

With the gun and mount hardware free of grease and oil, it’s

time to pull out the tools. You don’t need much when utiliz-

ing predrilled screw holes: the correct screwdrivers or Allen

wrenches, a small mallet, and a tube of Loc-Tite or similar

thread cement (Figure 37). Using the right screwdriver is an

absolute must. To tighten the screws sufficiently without

jumping, the driver must fit perfectly in the screw head slot.

It must have a hollow-ground blade with parallel sides, and

the blade should be long and thick enough to fully engage

the slot. When you don’t have the correct size at hand, grind

one to fit the screw. Improperly fitting driver blades are

bound to jump from the slot, and the damage they do is all

too clear. Damage such as mangled screw heads that may be

next to impossible to remove, scratched rings or mounts or

barrel finish, and gouged stocks. These are immediate and

unmistakable signs of amateurish scope installation.

Some mounts use Allen screws. Naturally, these are easier to

work with as long as the head is heavy enough to take the

necessary pressure involved in tightening. Some 6-48 (stan-

dard sight-mount screw size) Allen heads are rather dainty,

so if the least bit of rounding occurs, back the screw out and

start over with a fresh one.

66

FIGURE 36—Thoroughly cleanand degrease gun and mountsurfaces before beginning anyscope installation. Even theslightest bit of give, magnifiedunder recoil, can lead to aloose mount and in extremecases can result in screwsshearing off.

Gun Sights 67

Keep in mind that scope mount screws must be very tight.

It’s possible for a strong-armed gunsmith to twist off a 6-48

screw, but with even, judicious pressure, this should not

happen. Another way to achieve an extra degree of tightness

is to rap smartly on the screwdriver handle with the mallet

as you make the last turn. This can often account for anoth-

er quarter turn without compromising the screw’s strength.

For especially hard-recoiling magnums and on very light

“mountain” rifles, it may be wise to substitute heavier 8-40

screws, a measure some manufacturers already provide on

certain current pump, lever, and auto rifles. This of course

means retapping the base and receiver screw holes.

Double-check to make sure the base(s) is correct for the gun.

Position the bases and start the screws until they’re snug

but not tight. Then, alternating between each screw, finish

the tightening job, taking up a half, then a quarter, turn at a

time until there’s no more looseness. It’s a good idea to coat

the screw threads with a drop or two of Loc-Tite to guard

against loosening.

Caution: Use Loc-Tite and similar metal adhesives sparingly,

however, since it may be necessary to break the bond some-

day. Also, any excess could seep down into the receiver and

freeze or otherwise interfere with moving parts.

FIGURE 37—The fundamentaltool needed for nearly all sightmounting jobs is a top-qualityscrewdriver. The screwdriver(s)should have hollow-ground, flat-sided blades that completely fillthe screw head slot. Allenheads should contain hardenedsteel to avoid “rounding off” as the screw tightens.

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Self-Check 3

Indicate whether the following statements are True or False.

_____ 1. Coated lenses and tubes sealed with nitrogen gas are two of the major factors inscope development.

_____ 2. Handgun scopes must offer extended eye relief.

_____ 3. Top mounts, like the popular Weaver series, generally attach to the top of thereceiver or barrel with screws.

_____ 4. The first thing to do when shots fail to form a group during sighting-in is to checkthat mount, ring, and action screws are tight.

_____ 5. “No-gunsmithing” pistol mounts usually clamp onto the top strap or another part ofthe frame.

_____ 6. Modern scopes reproduce the image at about the same location as the shooter’seye.

_____ 7. Parallex occurs on images beyond 150 yards.

_____ 8. Because big game is generally more active at twilight, hunters can often benefitfrom scopes with large objective lenses.

_____ 9. When something goes wrong inside a scope, it can usually be repaired on the spot.

_____10. Bulls-eye shooters usually prefer a “duplex” scope reticle.

Check your answers with those on page 98.

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DRILLING AND TAPPING

Attaching mounts where no screw holes are present is a

more involved process, as it requires proper alignment and

drilling and tapping. Correct screw hole positioning will

depend on the type of mount, but it’s always wise to set up

this work in a drilling jig like those from Brownells and

Forster. A drilling jig will ensure that the screw holes are

true to the bore while facilitating correct drill and tap tech-

niques. At the very least, you must align the barreled action

in a padded vise on a level drill press table.

Note: Step-by-step drilling and tapping instructions follow

this procedural overview.

1. You should position bridge-type (one-piece) top mounts

so that the mount’s recoil shoulder (when it has one)

butts tightly against the rear of the receiver ring. Be sure

that any holes drilled in the receiver bridge are at least

inch from either edge. Position Weaver and most two-

piece mounts where they won’t interfere with

loading/ejection ports or the seating of locking lugs.

2. When employing a drill jig, some mounts may require

adjustment of the drill arm. You can do this without dis-

turbing correct alignment. When you don’t use a jig, drill

and tap one hole only, then attach the mount securely,

re-level if necessary, and center-punch the remaining

hole(s).

3. You secure side mounts by screws and/or taper pins.

Weaver and other firms currently offer a wide selection

to fit various modern rifles. They often attach by means

of a screw-on base plate shaped to fit specific receiver

walls. To determine the mount/base position (when not

utilizing predrilled holes), separate the barreled action

from the stock and place it (leveled) in a vise. Secure the

scope in the rings, join the mount and base plate, and

hold the arrangement in the desired location against the

receiver. On most guns this will be 1/4 to 1/2 inch in

back of the receiver ring. Clamp the arrangement in

place, and use a level to ensure that the mount is true

to the bore. Center-punch the middle screw holes, then

remove the mount/base and drill and tap these holes.

Always use a drilling jig when possible. Reattach the

mount/base and repeat the procedure for obtaining the

remaining screw holes. Use a Dremel tool to flush the

finish screws and pins to the inside of the receiver and

use a small grindstone to smoothly polish them.

4. You can accomplish side-mount installations on certain

lever-action rifles and shotguns by securing the mount

in holes provided for action or trigger assembly taper

pins. Secure the barreled action in a vise, then drive the

original pins out right to left with the muzzle pointed

away. Replace one pin at a time, inserting them left to

right, to avoid misaligning moving parts.

5. Most pistol mounts fit existing features, either clamping

to the top strap/rib, frame, barrel, and even the trigger

guard, or utilizing the rear sight screw hole. Ruger, for

example, mills their revolver ribs to accept clamp-on

rings, and single-shots like the T/C Contender and

Remington XP-100 come pre-drilled.

6. For some handgun mounts, however, you’ll have to drill

and tap screw holes. You must center and align them

with the bore on the revolver’s top strap, or on the slide

when using a side mount system on an auto loader.

Begin by leveling the frame or top strap in a padded vise,

then position the mount directly in line with the bore.

It’s also wise to file-fit the bottom of the base so that it

perfectly fits the gun’s contour. Clamp the base in place

and center-punch the screw holes through it. Separate

the base to drill and tap the first hole, then reattach to

confirm the position of the remaining holes. Pistol bases

must bear the brunt of fierce recoil, so be sure to

degrease all bearing surfaces and threads prior to final

installation, and use Loc-Tite to anchor the screws.

Grind and polish screws flush to inside surfaces with

a Dremel tool or files and emery cloth.

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Gun Sights 71

Drill and Tap Procedures

A professional gunsmith will have a good drill press in his or

her shop. In no other type of gun work is this tool more

essential than when mounting sights. Hand drills can make

the screw holes, but without a press there’s no way to ensure

that they’ll properly align. A crooked sight is about as worth-

less as no sight at all, and to make matters worse, the gun

can become permanently marred if you make a mistake

aligning the holes.

For gun sight work, a drill press should have certain fea-

tures. You need a compound vise to put the work in the

proper position and to hold the gun steady and square. A

depth indicator and a positive depth stop are vital to prevent

over-deep holes and the ultimate error-penetrating the bore.

You also need good chuck that will close down tight enough

to grip drills as small as 3/64 inch when you make tiny holes

to roll pin a front sight blade.

The necessary drills will be smaller sizes; Nos. 28 and 31

wire gauge will get the most work, but you should have on

hand a wide selection, up to No. 16 perhaps, in the event

that some oddball job shows up. Short-length drills allow

more precision, have less “bend,” and are perfectly adequate

for shallow mount holes. Carbon steel drills will handle most

jobs as long as you don’t run them so hot to draw the tem-

per, as many gunsmiths today prefer the high-speed steel

type. For extremely tough receivers (the 1903A3 Springfield’s

hardness is legendary) solid carbide drills may be in order.

These, however, are quite expensive and must not be used

in softer steels. Additionally, a center drill will come in

handy. This is one that’s made extremely rigid by an over-

sized shank before ending in a very short drilling tip. Center

drills are ideal for starting and centering a hole, and to free

broken screws and taps.

As noted in the earlier sections on metallic sights and

scopes, a proper drilling jig is a great advantage in sight

installation.

Tools like the Forster Universal Sight

Mounting Fixture or Brownell’s SSR

Mounting System are engineered with broad

adjustment capability to secure and set up

virtually any long gun (Figure 38). You can

arrange the Brownell’s unit to accommodate

handguns and to install ribs. Such tools are

expensive, but the precision they facilitate

and the time they can save should profit

anyone mounting sights on a regular or

volume basis.

Both the Forster and Brownell sight mount-

ing jigs secure the gun by clamping it to

leveled V-blocks, and each provides a sliding

drill arm that travels slots parallel to the

V-block alignment. The drill arms, which

secure interchangeable bushings for both

drilling and tapping, move to the precise

location of the desired hole and lock into

place. Positioned directly over the top of

the gun, the superhard steel bushings

won’t allow drills or taps to flex or “wander.”

When you set up the work in these V-block

arrangements, screw holes are true to the

center of the bore and in perfect alignment

with one another.

B-Square’s Professional Drill Jig is a specialized fixture

made to position screw holes for popular scope mounts

on Springfields, Mausers, U. S. Enfields, and other similar

military bolt actions. It comes with interchangeable bars

(depending on the rifle) that furnish the correct hole spacing

in reference to the recoil shoulder, and also accepts various

bushings. B-Square also makes a mini Barrel Sight Jig that

combines a V-block base fitted with two No. 31 bushings and

a U-clamp that encircles the off-side of the barrel (Figure 39).

Gun Sights72

FIGURE 38—With the work secured in a Forster jigclamped to the press’s compound table, you canproceed drilling with assurance that the holes willalign perpendicular to the bore. The No. 31 drill,which matches the 6-48 screw, is the most commonsize for sight work.

Gun Sights 73

Another very similar jig is the Top Dead Center tool. With

both tools, you must first level the barrel in the vise, then

slide the jig to the correct placement and level it. This centers

the holes and makes them perpendicular. However, these jigs

are limited to use on round barrels and won’t service

receivers or pistol slide mounts or the like.

Whatever sight mounting fixtures are most practical given

the cost and the volume/type of work they’ll perform, they’re

virtually a must for professional sight mounting. Without

them (or some similar tool), you must make do by using the

mount itself as a guide and rely on squares, a center punch,

and a huge amount of luck.

The center punch, by the way, probably won’t be necessary

when using a close-fitting jig. Nevertheless, it behooves any

busy gun sight installer to keep some on hand just in case.

And when working without a jig, a 60 degree high-speed steel

punch inserted through the mount’s predrilled screw holes

will provide adequate hole positioning, so long as the work is

true. Keep in mind, however, that the impact of the punch

will further harden the surface of the steel.

We advise you that tapping proceed immediately after drilling

without disturbing the setup. Sight mounting work won’t

require a great variety of tap sizes. However, you should make

those on hand from the best quality carbon steel. Again,

some gunsmiths prefer those made from more expensive

high-speed steel. The 6-48, 3-56, and 8-40 sizes will be the

ones most frequently employed for sight screws, so a reason-

able quantity-enough to allow for some unavoidable breakage

is necessary.

FIGURE 39—B-SquareBarrel Sight Jig (Drawing

courtesy of B-Square,Fort

Worth, TX)

Note: The sizes we’ve mentioned so far aren’t the only sizes

you may need. You find a good selection that will cover near-

ly all sight mounting jobs in Brownell’s Drill & Tap Kit No. 2

(Figure 40).

Keep in mind that three different taps are necessary for any

screw hole that bottoms out without going all the way

through-the majority in sight mounting. The taper tap is

so-called because its long, gradual taper brings more teeth

to bear at a time; it’s the starter. The plug tap, with a bit less

taper, enlarges the hole and makes the threads more uni-

form. The bottoming tap has no taper and is flat on the end,

and is used to finish the hole.

Best for turning the taps is a T-handled wrench with an over-

head spindle that extends into the drill chuck. This ensures

that the tap work will line up precisely with the drilling. The

wrench turns freely (by hand power only, never using the

drill motor) on the spindle yet has no lateral movement that

could compromise the work or stress the tap. When using

tap wrenches lacking the connecting spindle, we strongly

advise you to have some kind of guide bushing in place to

Gun Sights74

FIGURE 40—Brownell’s Drill &Tap Kit No. 2 (Photo courtesy

Brownells Inc., Montezuma, IA)

Gun Sights 75

prevent canting the tap. A possible alternative is the hand-

held Taprite Tap Guide, which will support the tap and keep

it from threading on a slant.

Drilling and tapping the small holes required for sight

mounting screws in hardened steel can be delicate work.

It is wise, then, for the beginner to practice first on pieces

of scrap steel before applying these techniques to a gun.

Drilling

The drilling procedure you use will depend

on whether or not you use a drill jig. When

you do use one, begin by determining maxi-

mum safe hole depth with a caliper or

micrometer, then setting the depth stop in

the drill press accordingly (Figure 41).

Before turning on the motor, lower the drill

once again to ensure there’s no binding as it

enters and passes through the bushing.

Be sure drills are sharp; if a point doesn’t

immediately take hold with moderate pres-

sure, it needs sharpening. Apply firm,

steady pressure, but never so much to

cause the drill to “spring.” This could result

in an enlarged, out-of-round hole, or a bro-

ken drill. Use plenty of top-quality cutting

oil, such as Tap Magic or Brownell’s Do-

Drill (STP motor lubricant will work in a

pinch), throughout the operation.

When no drilling jig is available, you must

secure the work in a padded vise mounted

to the press table, and true it with a try

square and level (Figure 42).

FIGURE 41—Before beginning any barrel drilling jobit’s absolutely essential to determine how deep thehole can be and to set the depth indicator/stop onthe drill press accordingly. A good rule of thumb isto leave at least as much metal as is removed. Lineup the work in the jig and true it with a level.

Gun Sights

Clamp the mount base in its intended position and level it,

then center punch one hole. (Completing work on one hole at

a time will ensure correct registration.) Remove the base and

begin the hole with the center drill, going only as deep as

the full diameter of the drill. Switch to the standard drill

and complete the hole. Move on to the next hole after tapping

the first and securing the mount in place with a screw.

Drilling and tapping hardened steel receivers may prove

extremely difficult, particularly when you don’t use a drilling

jig. You can usually remedy this by hand grinding off a tiny

spot of extra-tough surface metal before starting the hole.

However, the 1903A3 Springfield and some other receivers

have been hardened beyond surface depth and will require

spot annealing (softening) with a torch-at least for tapping.

Though annealing was once a virtual prerequisite for drilling

1903A3s, etc., the widespread use of today’s high-quality

high-speed steel and carbide drills makes it largely unneces-

sary. This does nothing to prepare the steel for tapping, so

there can be cases where spot annealing will prevent broken

taps and the frustration of removing them.

76

FIGURE 42—Always usetry squares and a levelwhen setting up drill andtap jobs. It’s preferable tosecure the barreled actionin a drilling jig or at thevery least a padded vise.

Gun Sights 77

Drill the holes as needed, then polish around them with

emery cloth; the polished spots should be about 5/16 inch

wide. Using a needle tip, set the oxyacetylene torch for a low,

lean flame and heat the metal-one spot at a time-to a deep

blue. Be careful not to let the steel begin to turn red or fur-

ther hardening will occur. Withdraw the flame slowly to allow

gradual cooling, then repeat the polishing/heating routine

two or three more times until the steel remains blue, rather

than brightening, when polished. You follow the same proce-

dure when it’s not possible to predrill holes, expect that

you’ll need to begin by spotting with a small hand grinder,

removing about inch of surface metal before heating. Don’t

begin drill or tap work until the metal has thoroughly cooled.

Tapping

Again, we highly recommend that you perform this job

through the bushing in a jig, using a wrench with a spindle

extension that you can secure in the drill press chuck. This

will hold the tap straight, evening out the pressure all

around, helping to prevent chipped teeth or even breaking

the tap (Figure 43).

As in drilling, it’s essential to freely use a

high-grade cutting oil. Turn the tap a half

turn then back off a quarter, turn and back

off. It may be smart to back the tap all the

way out on occasion and clear accumulated

chips. Stop tapping at once if you begin to

feel the tap give without actually turning in

the hole. Likewise, if the tap squeaks or

grinds, this probably means the tap isn’t

sharp enough. You need to either sharpen

it or swap it for a new one. Quit with the

taper and plug taps when you feel their

points bottom in the hole. Be sure to clean

out chips with a magnetic tip and debur the

surface with emery cloth before starting

screws.

FIGURE 43—It’s preferable to use a T-handled tap wrenchwith a free-turning extension spindle for threading sightholes. For the greatest precision, disturb the setup as little as possible when switching over from drilling to tapping, and engage the spindle in the chuck.

Attaching the Rings

Attaching the rings to the base is the next step. Separate the

halves of split rings (set aside the tops of those that come

apart horizontally) and if the base contains slots, indents,

or other recoil shoulders, be sure to properly seat the ring

clamps in these references. On Weaver-style bases, there’s

sometimes a small bit of play between the clamping screw

and its slot. So, be sure to check this and tap the rings for-

ward with a small mallet before tightening the screws. Also,

be sure not to confuse the old-style round clamp screw with

a new-style square base slot or vice-versa (Figure 44).

On the Redfield Jr. and other socket-type fixtures that are

rotated into a secured friction fit, use a screwdriver handle,

a dowel, or small piece of pipe rather than attempting to

crank it in with the scope. Do this a time or two until it

seats properly before setting the scope in place.

Note: It’s not unusual to find overly long mount screws that

bottom out before getting really tight. In the case of Weaver

clamp screws, it’s also not unusual to find screws that pro-

trude into the screw head slot and make it impossible for the

driver to gain a solid hold. You must shorten them, taking

care not to damage threads.

Gun Sights78

FIGURE 44—Reliable yet inexpensive, the Weaver topmount is probably the all-timebest-selling scope mount.Weaver top mounts fit thereceivers of practically all modern rifles. Before tighten-ing the ring screws duringinstallation, tap the ring for-ward to be sure no play existsin the crossbolt slot.

Gun Sights 79

Positioning the Scope

The exact position of the scope depends largely on the shoot-

er’s personal eye relief, which won’t be the same from one

individual to the next. For that reason the shooter should

be present when the scope is being mounted.

For rifle and shotgun scopes, the shooter stands or sits

shouldering the gun as he or she would in a normal firing

position. Be especially sure that the head is in its natural

position on the stock. Also, the shooter should wear clothes

he or she wears when using the gun. For cold-weather hunt-

ing, this means heavy garments or several layers. Handgun

shooters should grasp the gun with their customary hold,

but they may also need some external support.

Ensure that the rings are the correct size for the scope tube

and determine the desired ring height. Rings generally come

in low, medium, and high variants; of these, low rings are

the most popular. Optimum height depends on how the

shooter cheeks the stock. Raising one’s head from the

cheekrest to see through a high scope leads to poor shooting.

However, the size and position of the scope’s ocular bell may

also require higher rings to clear a bolt, hammer, safety, or

other moving parts. At times you can alter the part, such as

changing the angle of the bolt handle or adding a hammer

extension, but a simpler alternative that works in many

cases are extension rings. These are offset from the bases to

allow the scope to be placed out of harm’s way. Unfortunately,

you can only slide a scope so far in either direction before

compromising eye relief. When this happens, high rings,

a gunsmithing alteration, or a different scope may be the

only option.

Place the scope in the rings and tighten the screws until they

hold it snugly but still allow it to move. Then slide the scope

toward or away from the shooter’s eye until the shooter sees

the entire field of view. With modern rifle scopes, this eye

relief zone may extend an inch or more, so for the sake of

speed it may be preferable to find the midpoint. On hard-

kicking magnums, it’s wise to place the scope toward the

front of available eye relief (that is, with maximum distance

between the scope and the eye). This makes it less likely for

the shooter to get conked on the head during recoil.

Once you determine proper eye relief, set the gun in a padded

vise or cradle and make sure it’s level. Without disturbing

the position of the gun, rotate the scope (taking care not to

shift it forward or backward) until the vertical crosshair or

post is also perfectly vertical. This step prevents scope canti-

ng, which can lead to sighting errors. Tighten the screws

with partial turns, alternating from side to side and ring to

ring. Don’t attempt to secure any one screw or either side

too quickly, or the scope may become pinched off its vertical

axis. Alternate tightening allows even spacing where the ring

halves meet. Ideally, the halves should be in contact, but this

isn’t always the case. Small gaps are sometimes present. For

strength and looks these gaps should be even, so you can

fill them with tiny spacers. It’s not necessary for ring screws

to be so absolutely tight as mount base screws, and over-

tightening can mar or dent the scope tube.

Sighting may reveal that the scope doesn’t have sufficient

adjustment to obtain the desired zero (this rarely occurs

with late-model guns, but it can crop up on older military

conversions, air rifles, and others). Then you can remount

the scope in adjustable mounts or by using shims. There

are a number of adjustable mounts on the market, some for

both elevation and windage, some for one direction or the

other only. Don’t confuse them with micrometer-style target

mounts that must make fine adjustments for scopes with

fixed reticles. Rather, they’re limited to gross adjustments

and must be used in concert with internal adjustment. When

using one, begin it at the middle of its adjustment range,

then move it only when necessary.

Gun Sights80

Gun Sights 81

Shims, both manufactured and homemade, can also solve

minor elevation deficiencies. Factory shims made of super-

thin steel or other material fit under mount bases and come

predrilled in various combinations to match the bases’ screw

holes. You can fashion home versions using anything from

steel sheeting to an old business card. When using any

material that has even the slightest degree of “give” (like

paper), be sure that screw tightening has crushed the “give”

out of it. Similarly, you can cut a shim to fit the inside of a

ring; electrician’s tape (sticky side down) makes for a neat job

and can be used in two or three layers. “Crushed” under the

pressure of the ring screws, it will also ensure against scope

slippage. For aesthetics’ sake, you should touch up any

shims that are visible after installation with black ink or a

bluing retouch marker (Figure 45).

FIGURE 45—Birchwood Casey offers a trio of touch-up pens designed to make it “quick and easy” to keep bluedsteel and black anodized aluminum or other black-painted metal surfaces looking good on guns. (Photo courtesy

Birchwood Casey, Eden Prairie, MN)

Gun Sights82

Self-Check 4

1. You should use _______ _______ like Tap Magic and Brownell’s Do-Drill during drill andtap operations.

2. You may need to spot _______ with a torch to produce screw holes in 1903A3Springfields and other hardened receivers.

3. When tapping a screw hole, never apply _______ _______ if the tap begins to squeak orgrind.

4. A _______ tap enlarges a drill hole and makes threads more uniform.

5. Using a tap wrench with a spindle extension secured by the drill press chuck holds thetap _______.

6. The drills that get the most work in sight-mounting jobs are Nos. _______ and _______wire gauge.

7. A gunsmith’s drill press should be equipped with a chuck that will close tight enough tohold a _______ drill.

8. A _______-bodied, _______-tipped center drill is useful for starting a hole.

9. Using a drilling jig, like those from Brownells and Forster, is the best way to ensure_______ _______ sight mount holes.

10. Drilling jigs feature interchangeable super-hard steel _______ to keep drills from “wandering” off precise screw hole locations.

Check your answers with those on page 98.

Gun Sights 83

SIGHTING-IN

With the scope successfully mounted, it’s now time to zero

the rifle’s shots to hit where the reticle indicates. This is

somewhat easier to accomplish with a scope than iron sights,

since the aiming point is so much more precise. By employing

the correct techniques, you can complete sighting-in quickly

using less than a box of ammunition. By contrast, an unpre-

pared trip to the range can cause no end of frustration.

Before you commence the sighting-in, and even before you

touch the first adjustment knob, you must focus the scope

for the shooter’s eye. You can do this anywhere, though out-

side using a neutral background free of distracting elements

is probably best. It’s also useful to view some distant objects

during this procedure.

If the shooter is going to wear glasses or contact lenses when

using the rifle, it’s important for him or her to have them on

at this time. Quickly look through the scope at the sky or

some other well-lit, uncluttered background and note the

sharpness of the reticle. If it takes a moment for the eye to

bring the background into focus, then you need to refocus

the scope. Suppose it’s immediately sharp and clear all the

way to the end of the crosshairs and

remains so when you repeat the exercise a

few times at, say, three minute intervals.

Then, reposition the scope to look at some

object 100 yards or more away. If the eye

can shift back and forth from the crosshairs

to the object and both remain sharp without

a momentary lapse, then you don’t do any-

thing further (Figure 46).

FIGURE 46—For those who prefer sighting-in on roundbulls-eyes, Birchwood Casey offers a target spot assort-ment for creating instant bulls-eyes. The target spots areprinted with a high contrast, radiant-red fluorescent colorthat effectively creates a sharper sight picture and bulletholes which are more clearly visible. (Photo courtesy

Birchwood Casey, Eden Prairie, MN)

You correct unsatisfactory focus by loosening the lock ring,

and turning the ocular lens in or out until a tack-sharp,

quick-glance focus is evident (being careful not to screw it

all the way off). Repeat this test several times, being sure to

refocus the eye on something else during the look-away inter-

vals. Lock the eyepiece into place and the focus should

remain correct so long as the shooter’s vision is the same.

Because everyone’s eyes are different, it’s essential that you

set the focus for the person who will use the scope.

Bore Sighting

Bore sighting is a handy shortcut to establishing a zero. You

accomplish bore sighting by aligning the reticle on a down-

range target that appears centered when looking directly

through the barrel. Most shooters favor a round bulls-eye,

but this method will also work with some kind of “X” or

cross, or even with target squares (Figure 47).

Bore sighting works best with bolt actions and single shots,

but it can work with levers, pumps, and semiautos by

employing a chamber inspection mirror.

Begin by securely resting the rifle on a bench rest pedestal,

sandbags, or some other solid rest. Remove the bolt, open

the action, or position the mirror-whatever it takes to get a

clear look down the bore. Shift the gun until the target is as

perfectly centered as possible.

Gun Sights84

Gun Sights 85

From this point, you must be very careful not to move the

gun even the slightest bit. Proceed to look through the scope

from the normal shooting position. In all likelihood, you

won’t find the reticle lined up on the target. Hold the rifle

firmly, still taking care not to move it at all, and very gently

turn the internal adjustment screws or knobs until the reti-

cle is precisely imposed over the target (Figure 48).

That’s all there is to bore sighting, but keep in mind that it’s

not an exact science. It’s likely to put the first shots some-

where on the target paper, but further fine-tuning will be

necessary. Most shooters bore sight at 100 yards, the dis-

tance they’ll be zeroing for. Even though most know enough

to use very large targets, there are times when the shooter

won’t find shot holes when the test firing finally begins. This

FIGURE 47—Those who prefer precision squares will appreciate the superimposed grid pattern offered onBirchwood Casey’s traditional targets. Each target contains multiple faces for more shots per sheet. (Photo cour-

tesy Birchwood Casey, Eden Prairie, MN)

Gun Sights86

can occur when barrels are slightly bent or the scope is

slightly out of alignment with the bore, but even these guns

can be bore sighted, zeroed, and shot accurately. The answer

here is to move the target closer-50 yards, 25 yards if need

be. Repeat the bore-sighting procedure and try a shot or two.

When you find the shots at closer distances, it may be neces-

sary to bore sight again when the target is farther down

range.

Modern technology provides a gadget to bore sight any type

of scope indoors. This handy little device is a collimator, and

for anyone responsible for bore sighting or zeroing several

guns, it can be a real time-saver. At the heart of the collima-

tor is a close-tolerance rod called a spud that extends a cou-

ple of inches into the muzzle. You then attach the spud,

which you select to fit the bore diameter, to a small optical

unit containing visible crosshairs and reference marks, or

FIGURE 48—When bore sightinga rifle, the procedure begins bycentering the target as oneviews it through the bore (bot-tom). Then, adjust the scope’scrosshairs until they also centeron the bulls-eye for a reasonablyreliable preliminary zero.

Gun Sights 87

perhaps a grid. The user simply aligns the scope’s reticle

with the collimator’s horizontal and vertical axes and the

optical bore sighting is complete. Again, even a slight bend in

the barrel will fool the collimator. In such cases, revert to

conventional bore sighting at short range (Figure 49).

Final Sighting

Though bore sighting or using a collimator will usually put

one “on the paper,” you should still the take a gun out to the

range and ascertain its zero at a suitable distance. Most

often the distance for centerfire rifles is 100 yards, the com-

mon length of U. S. rifle ranges. This makes for convenient

scope sight adjustments, since each click will move the cor-

responding reticle a fraction of an inch per 100 yards. Most

click adjustments nowadays are good for one-quarter inch at

100 yards, but you’ll also see scopes with one-third and one-

half inch graduations.

You should zero rimfire rifles and slug shotguns at 50 yards,

since 100 is at the upper limit of, or beyond, their effective

range. Likewise, you should sight-in scoped pistols at 25

yards, unless they’re long-barreled single-shots chambered

for a rifle cartridge, whereupon 50 or 100 yards would be

more appropriate.

FIGURE 49—Containing a grid orcrosshairs in its small opticalscreen, a collimator allows con-venient preliminary sight-in justabout anywhere. One selectsthe correct interchangeablespud to match the size of thebore, inserts it in the muzzle,then adjusts the scope reticle to overlay the collimator’s reference markings.

Gun Sights

You should do all sighting-in work from an absolutely solid

rest. At the very least this means sandbags on a stable

shooting bench. A formal bench rest pedestal equipped

with an elevation wheel and accompanied by a rear bag is

markedly better. Relying on a balled-up jacket or a small,

clamp-on bipod is often a futile exercise. Handgun shooters

will achieve even better results with a Ransom Rest, a spe-

cialized clamping device that completely supports the pistol,

which in turn is fired by a lanyard attached to the trigger.

To achieve the final sighting, sit comfortably and lean into

the gun in the classic bench rest posture. Square the butt

securely on your shoulder, grip the stock wrist lightly with

your trigger hand, and use your off hand to pinch minute

aiming adjustments into the rear bag. On particularly hard-

kicking guns, you may need to use your off hand to control

the forend, which has the tendency to jump off the rest.

When that happens, the shooter usually gets smacked by

the scope, something no one really enjoys.

Fire the first shot and then find it on the target. You can

often see it through the scope (depending on the magnifica-

tion power and the bullet’s caliber), but a surer bet is to use

a spotting scope (Figure 50).

If it doesn’t appear through the optics at hand, then you may

have to walk down-range-only when safe to do so-and locate

it. If the bullet hole isn’t on the paper (allow for plenty of sur-

face area when getting started), move the target closer by at

least half the distance and try again.

If the first bullet hole isn’t more than several inches from the

point of aim, continue firing a three-shot group. Figure that

the gun’s average point of impact is the center of the three

shots. That point must be moved to occupy the same spot

as the original point of aim, a shift accomplished with the

scope’s internal adjustments. Use a coin or screwdriver to

make the change unless the scope has knob adjustments.

It’s important here to estimate the required move and to

know exactly how far each adjustment click will move the

shot. The adjustment mechanisms of modern scopes are very

reliable, but occasionally they’ll hang up, a commonplace

mishap with older models. If the reticle doesn’t seem to

respond, give the turret a sharp rap with your knuckle and

fire another shot.

88

Gun Sights 89

Should the first hit land way off the mark, however, make

the initial sighting change right away-no need to fire three

rounds out of the ballpark. If several subsequent shots fail to

form a group, recheck all mount, ring, and action screws.

They must be tight! Poor shooting technique or an unstable

rest can also lead to unsatisfactory groups. Some loads sim-

ply perform poorly in a given gun; if this happens, try a dif-

ferent load. The purpose here isn’t to shoot tack-hole clus-

ters, but they must be tight enough to provide a definite

point-of-impact reference.

Note: Always make it a practice to center groups, not indi-

vidual shots. Continue with three-shot groups throughout

the zeroing procedure.

Make adjustments with purpose; figure the number of clicks

needed to move the group and make them. Don’t creep to the

center of the target. When a gun is grouping satisfactorily,

it shouldn’t require more than three or four adjustment

series to reach the desired zero. Be sure to allow enough

time between shots, however, to prevent barrel heating from

producing “fliers.”

FIGURE 50—Bushnell’s 18-36XSentry spotting scope provideswide field viewing at low powerand sharp close-up detail at high power. A built-in peep sight aids fast target acquisition.(Photo courtesy Bushnell, San

Dimas, CA)

Scope zeroing is a service extended by many professional

gunsmiths after performing work or following the purchase of

a new firearm or scope. For the most part, a gunsmith can

establish a workable zero for the gun no matter who subse-

quently shoots it. There will be minor differences from person

to person, however, due to the way each one shoulders or

grips it. By all means prevail on customers to get out and

practice, if for no other reason than the safety factor of being

familiar with one’s equipment.

Unless you have several guns to sight-in, this practice can

eat into valuable shop time. You can charge a fee for the

service of course, though if it’s reasonable-say $25-it will

probably just cover expenses. Don’t overlook the customer

service value and the goodwill generated. These certainly

contribute to the gun professional’s reputation. In the long

run, this kind of extra effort could pay solid dividends.

Alternately, you could limit such service to bore sighting or

collimating. For the majority of customers this will be entirely

satisfactory-even at the cost of a few dollars. They’ll soon

head for the range to try out the new or repaired gun or the

new scope. When the gun and scope leave the shop with pre-

liminary sighting-in already accomplished and the first shot

prints cleanly on the target, it reflects on the gunsmith’s pro-

fessionalism. Be sure that the customer realizes that bore

sighting is merely a preliminary measure, and he or she still

needs to complete the sighting-in job. Done in-house with a

collimator, this will require only a few minutes. Also, if you

do it in the customer’s presence, he or she will likely leave

with a greater degree of confidence in the purchase or the

work that you performed.

Bolt Handle Alteration for ScopeMounting

On certain older military bolt-action rifles, it’s necessary to

change the angle or shape of the bolt handle to clear a low-

mounted scope. On these rifles, a scope can prevent the han-

dle from rotating into its uppermost position. They include

the 1903 Springfield, Krag, Arisaka, and Mauser. Other rifles

may need bolt alteration. You can achieve the alteration in

Gun Sights90

Gun Sights 91

two ways: 1) by forging the handle with a torch and bending

it, or 2) by hacksawing the old handle off, leaving a stud onto

which you weld a reshaped or custom handle. Most gunsmiths

usually prefer the second method, since it subjects the bolt

to somewhat less heat. Both methods require advanced gun-

smithing skills and only those who have the proper training

should attempt them. The intense heat involved in both

cases can damage locking lugs and other bolt parts if it’s not

confined to the handle.

In addition to the welding apparatus and basic shop tools

needed (hacksaw, grinder, files, etc.), there are a number of

specialized commercial jigs that facilitate these conversions.

Among these are the Three V Bending Block for the forging

method, and Brownell’s Bolt Welding Jig for cut-and-weld

jobs. Another valuable aid offered by Brownells is a heat

sink, a fixture that screws into the rear of the bolt and draws

heat away from the rest of the bolt body. These come threaded

for Springfield, Mauser, and Enfield bolts, and we recommend

you use them in conjunction with that firm’s Heat Stop, a

paste that effectively controls the transfer of heat within a

bolt.

Note: Heat Stop may also be beneficial in any sight installa-

tion that involves direct soldering or welding.

Procedure

You perform bolt handle conversions as follows. We stress

once again that only qualified individuals should perform

these tasks.

Forging. Disassemble the bolt, insert a heat sink in the rear

end, and coat the entire bolt body with plenty of Heat Stop

paste. Secure the bolt body in a Three V block or similar tool,

and place the arrangement in a heavy vise. With a large jet in

the oxyacetylene torch, heat the bolt handle quickly until it’s

cherry red and the metal is almost molten. Take care not to

scorch the steel by allowing it to contact the bright, central

oxygen cone visible within the flame, and make sure the

locking lugs and bolt face don’t heat up.

Grasp the knob with a forming tool (a flat piece with a

tapered hole at one end) and pull it downward to create a

right angle just out from the bolt body. Curve it up at the

very end so the knob will clear the stock, and if desired for

looks, rake the handle back a bit. (You can also bend it with

a medium-weight machinist’s hammer, though not with the

same degree of control.) Allow the setup to air cool slowly

before removing it from the block. After removing the Heat

Stop, file off any heat scale, regrind the bolt handle to its

original width if any deformation has occurred, and polish

it with a buffing wheel or emery cloth.

Note: The above procedure differs slightly from that discussed

in Basic Metalwork and Machine Tool Operation. There are

various methods for forging bolt handles.

Welding. Disassemble the bolt, secure its body in a vise,

and hacksaw the handle with a diagonal cut running from

the edge of the shank taper (where it changes from flat-sided

to round) at a 45 degree angle. Often it’s necessary to anneal

the area of the cut. Just be sure not to allow the heated

metal to begin to turn from bluish-gray to red, as this will

reharden it. At this point, determine exactly how much you

have to shorten the handle to provide scope clearance and

cut off the excess. If you’re changing the handle’s shape,

forge it as described above, holding it in position in the vise.

As an alternative to the original, there are a variety of after-

market bolt handle knobs available for such conversions, and

many gun owners opt for one with better looks.

Grind the end of the remaining handle shank so that it forms

wide “Vs” at the weld joint along the angled edge of the bolt

stub. This gives the weld maximum surface area. Clean up

weld joint surfaces, insert the heat sink, and position/secure

both pieces in Brownell’s bolt welding jig or a similar fixture.

This will hold the work securely without the risk of displac-

ing it with an unintended bump and it allows convenient

access to both sides. Encase the bolt body in a heavy appli-

cation of Heat Stop paste. Proceed with welding, using a mild

steel rod for both arc and gas welders. Torch welders should

use a medium-sized jet, taking care not to pull away the

flame too fast. Fill in the “V” notches all the way, working

from the middle up and out to the sides until the bead slightly

Gun Sights92

Gun Sights 93

overfills the notch. Be sure the bead fills in solidly by guiding

any scale that forms off to the side where you can file it away

later. Timely completion of the welding will minimize the heat

reaching the rest of the bolt. Air cool, then check the weld to

make sure that it’s solid; fill in if needed. When the welding

is complete, remove any accumulated scale, then grind, file,

and polish to obtain a pleasing handle contour.

Quite often it’s necessary to cut a relief notch in the receiver

in order for the new bolt handle to close fully. With a milling

machine or files, shape this notch to match the handle shape.

Make it just deep enough so there’s minimal clearance on the

inside edge of the receiver and the locking lugs can fully lock.

Be sure that this position doesn’t interfere with the functioning

of safeties and cocking/extracting cams. It may be necessary

to reheat treat the entire bolt after welding or forging. Only

qualified persons should attempt this job.

Safety Replacement for Scope Mounting

Just as it’s often necessary to alter bolt handles when

mounting a scope on certain military (and similar) rifles, you

may also have to install a new safety. Original safeties on

military rifles, built into the back of the bolt, rotate vertically

in a semicircular arc that’s blocked by the eyepiece of practi-

cally any low-mounted scope. You need to use a safety with

an alternate operating movement with this type of mounting.

Fortunately, a number of replacement models are available.

Some replacements work in essentially the same manner

as the originals, except that their movement arc, shortened

from 180 degrees to 70 degrees, stops just short of the scope.

Others adopt the “side-swing” design from the Winchester

M70. This type rotates horizontally back toward the shooter,

never moving up toward the scope.

The task of installing aftermarket safeties varies with the

individual model. Some, like the Buehler Low Safety, may be

simply exchanged with no machining of other parts. Other

jobs, such as required for the Chapman and DeLorge

safeties, involve using a milling machine and preferably a

milling fixture, as available from Chapman. Still others, like

the Precise Metalsmithing and Dakota conversions, replace

Gun Sights

the entire bolt shroud, containing the new safety therein.

Regardless of the type, you must carefully fit them to ensure

sufficient cocking piece/sear clearance. Inadequate clearance

could lead to slam-fires or firing as the safety disengages.

Warning: Any such unintentional firing is dangerous, and

could lead to property damage, injury, or even death. The

serious consequences involved demand that only qualified

individuals attempt safety installation.

Carefully read the manufacturer’s instructions and be sure

you fully understand them before beginning the conversion.

If any questions remain, don’t hesitate to contact the manu-

facturer. It’s also wise to consult with a gunsmith experi-

enced in this kind of work.

Installation Procedures

Following are installation procedures for the Buehler and

Precise Metalsmithing safeties, as neither requires machine

work. Again, we stress that only qualified professionals carry

out this work.

Buehler. Disassemble the bolt, remove the old safety, then

screw the bolt sleeve back into the body. At this point the

Buehler safety is dismantled. Compress the spring inside

the hole in the mounting pin and slip the assembly into its

position in the bolt sleeve. Install the safety lever and secure

it with the setup screw. For smooth operation, bevel the

bearing surface on the left side of the cocking piece to a

45 degree angle. When installed properly, this safety cams

the striker clear of the sear while holding the bolt in the

closed position. Excessive wear on the sear and striker engag-

ing surfaces will sometimes allow the striker to protrude too

far forward (in the cocked position) for the safety to function

correctly. When this happens it may be necessary to grind

back the shoulder on the cocking piece. Check the manufac-

turer’s instructions for the correct clearance between the bolt

head and the striker engagement surface.

Precise Metalsmithing. Disassemble the bolt and with the

safety lever in the middle position, screw the new shroud/

safety assembly into the bolt body. The plunger will seat in

the detent slot when the shroud is in the correct position.

94

Gun Sights 95

Check to see that the bolt will close and that the safety trav-

els smoothly throughout its arc of movement. If there’s any

interference or binding in the safety, lightly file/polish the

safety detent at the rear of the bolt. The safety lever should

cam the cocking piece backward, providing positive clearance

between the cocking piece’s engagement ledge and the sear.

This clearance should be no less than .3 inch with the original

trigger, perhaps a little less with a modern replacement trigger.

Check this clearance with a vernier caliper or feeler gauge.

If it’s insufficient or when operation isn’t smooth, polish the

30 degree bevel on the cocking piece’s camming surface or

file the sear engagement ledge to shorten it as necessary.

Note: The contact face on the cocking piece engagement

ledge must be square and perpendicular to the bolt center

line. Also, when you perform any filing on bolt parts, you’ll

have to reheat treat.

Gun Sights96

Self-Check 5

Indicate whether the following statements are True or False.

_____ 1. Inadequate cocking piece/sear clearance never leads to dangerous situations likeslam fires or firing when the safety is disengaged.

_____ 2. When forging, heat with an oxyacetylene torch until the shank turns cherry red.

_____ 3. Altering bolt handles for scope installation is a job that can easily be performed bymost gun owners in home shops.

_____ 4. For low-mounted scopes on certain military bolt-action rifles, replacement safetiesmust shorten or redirect the movement.

_____ 5. Properly reshaped bolt handles never require receiver relief cuts and/or stock inletting.

_____ 6. When the Buehler safety is installed properly, it cams the striker clear of the sear.

_____ 7. Bolt alteration is accomplished in two ways: forging and welding.

_____ 8. Installing a Chapman and Delorge replacement safety requires use of a millingmachine.

_____ 9. The Three V Bending Block bolt alteration tool is used for welding.

_____10. The proper shape for bolt handle shank stubs prepared for welding is rounded.

Check your answers with those on page 99.

97

Self-Check 1

1. True

2. True

3. False. Match apertures are considerably smaller-.05 inch

is a common size and some are even tinier.

4. False. The right side should be a few thousandths of an

inch larger.

5. True

6. False. Shooters have resorted to applying bright paint on

the rearward face.

7. False. They used front and rear rifle sights as early as

1500.

8. True

9. False. You should never penetrate the bore when drilling

holes for barrel sights because this ruins the barrel.

10. False. These are rear sight styles.

Self-Check 2

1. Shotgun beads

2. military, law enforcement

3. circular

4. dots, outlines, inserts

5. color, head diameter, shank size/thread

6. short

7. combat

8. windage and elevation

9. hacksaw

10. square

An

sw

er

sA

ns

we

rs

Self-Check Answers98

Self-Check 3

1. True

2. True

3. True

4. True

5. True

6. False. This was a characteristic of earlier scopes.

7. False. Parallex occurs on very close images, usually

inside 50 yards.

8. True

9. False. You can’t repair the scope at the range or in the

field.

10. False. Big game hunters prefer a duplex scope reticle.

Self-Check 4

1. cutting oils

2. anneal

3. added pressure

4. plug

5. straight

6. 28, 31

7. 3/64 inch

8. fat, short

9. correctly aligned

10. bushings

Self-Check Answers 99

Self-Check 5

1. False. It could lead to slam fires or firing when the safety

is disengaged.

2. True

3. False. This requires advanced gunsmithing skills.

4. True

5. False. A reshaped bolt handle may require cuts or inlet-

ting.

6. True

7. True

8. True

9. False. It’s used for forging.

10. False. The bolt handle shank stubs are V-shaped.

Self-Check Answers100

NOTES

101

925 Oak Street

Scranton, Pennsylvania 18515-0001

Gun Sights

When you feel confident that you have mastered the material in this study unit, complete the following examination. Then submitonly your answers to the school for grading, using one of the exam-ination answer options described in your “Test Materials” envelope.Send your answers for this examination as soon as you completeit. Do not wait until another examination is ready.

Questions 1–20: Select the one best answer to each question.

1. When zeroing metallic rifle sights,

A. divide the front and rear barrel diameters by two and subtract the difference.

B. move the rear sight in the direction you want the shot tomove.

C. move the front sight in the direction you want the shot tomove.

D. file down the front sight.

2. Bore sighting means

A. mounting the scope as close to the bore as possibleB. being able to place the shots so that they are touching in

the bulls-eye.C. centering a target when viewing down the bore, then

adjusting the crosshairs to the same aiming point.D. using a shotgun with no bead or rib.

EXAMINATION NUMBER:

Whichever method you use in submitting your examanswers to the school, you must use the number above.

For the quickest test results, go to http://www.takeexamsonline.com

Ex

am

ina

tion

Ex

am

ina

tion

02530700

Examination102

3. Installing a Smith & Wesson-type adjustable rear sight on a Colt Government Model .45requires

A. removal of the Smith & Wesson logo.B. a ramp front sight.C. inletting a shallow recess into the top of the slide.D. drilling a slot behind the ejection port.

4. Scope sights have really won the public’s favor since

A. Kepler refined the telescope.B. Civil War snipers used them.C. mass production began in the early twentieth century.D. they were made brighter and more reliable following World War II.

5. The key to proper tap procedure is

A. a straight tap with sharp teeth, plenty of oil, and gradual turning.B. beginning with slightly undersized taps and finishing with slightly oversized taps.C. uninterrupted turning to ensure unbroken threads.D. letting the drill press motor do the harder jobs.

6. Today’s scope mounts are very easy to install because

A. the steel in modern rifle receivers is relatively soft, and therefore easy to drill and tap.B. they simply replace the factory iron sights.C. they can be attached by electromagnetics.D. they’re manufactured to fit factory-drilled screw holes and/or other design features.

7. Open sights, the most common of all metallic rifle sights past and present, consist of

A. two aperture sights. C. a long tube with no lenses.B. a shallow notch and a bead or post. D. an extra-large peephole.

8. A collimator is a handy device for gunsmiths because it

A. helps determine the correct height for scope rings.B. allows them to accomplish preliminary sight-in anywhere.C. helps the shooter judge the distance to the target.D. helps hold the gun straight for proper sight-in.

9. You level side-mounted rear aperture sight holes by

A. truing with try squares and/or a drilling jig.B. drilling just one hole at a time.C. bore-sighting with the sight clamped in place.D. placing a machinist’s square on the front sight.

Examination 103

10. Rifles that often need bolt handle alteration and safety replacement for scope mountinginclude

A. older military semiautos like the BAR, M-1, and AK-47.B. any rifle chambered for a magnum more powerful than .300 Winchester Magnum.C. lightweight “mountain” rifles.D. certain military bolt-actions, that is, Springfield, Krag, Mauser, etc.

11. Ideally, a drill press used for sight mounting should be equipped with

A. rubber bushings in the sight mounting jig.B. a handle with large knobs, interchangeable chucks, and carbide bits.C. one forward speed and reverse capability.D. a compound vise, depth indicator and stop, and a tight-closing chuck.

12. Which hand tools do you need for cutting a dovetail sight mounting slot?

A. A center punch and an oxyacetylene torch B. A Dremel tool, a cold chisel, and an emery cloth C. A scriber, a hacksaw, and a 60 degree file D. Vise grips, a hand drill, and taps

13. When applying heat for bolt handle forging or welding, one must never

A. allow scale to form.B. allow the bolt handle to get red-hot.C. use an electric arc welder.D. allow excess heat to reach the bolt’s locking lugs.

14. Competitive shooters favor rear aperture sights because the sights

A. facilitate natural sight alignment and precise adjustments.B. worked great for the buffalo hunters.C. are very easy to mount on dovetail grooves.D. don’t cause as much glare as open sights.

15. What are the two basic categories of handgun sights?

A. Paine and bead C. Windage and elevation B. Top-strap groove and beadD. Fixed and adjustable

16. Safety conversions are potentially dangerous! Always

A. checker the thumbpiece to prevent slippage.B. ensure that the new safety holds the striker or cocking-piece engagement ledge clear

of the sear.C. ensure that the safety can never be manipulated when there are rounds in the

magazine.D. affix the new safety to the cocking piece with a set screw or solder.

Examination104

17. Methods used for mounting shotgun beads are

A. screw-in or drive-in.C. cutting a dovetail in the rib or barrel.B. clamp or weld onto the ribD. with a Top Dead Center tool and a heavy hammer.

18. Essential tools for all scope mounting jobs are

A. C-clamps and a set of socket wrenches.B. a solder iron and a Dremel tool.C. a tight-fitting, hollow-ground screwdriver or Allen wrench and Loc-Tite.D. a soft brass drift punch, small mallet, and magnetic level.

19. When working on the sights of a handgun that has “fixed” sights, the most likely job is

A. replacing the hammer.C. milling a new rear notch.B. replacing the front sight.D. installing drill-rod pins through the old rear sight.

20. Scopes with high magnifications have advantages and disadvantages, such as

A. fine adjustment capability but small exit pupils.B. the target appears much closer but field-of-view is diminished.C. easy-to-see reticles but critical eye relief.D. small size but poor twilight capability.