Adjusting Hunting Rifle Scopes Using a Bore Sighter

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Figure 1A: Using a bore sighter.
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Any scope and rifle combination need to be fine-tuned if it's to perform well.
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Figure 2: Bore sighter aligned with barrel.
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Figure 3: Zeroing in.
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Figure 1B: Scope adjusted for windage.
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Figure 1C: Scope and bore sighter aligned.

Confidence in your gun equipment can be a key to more
successful hunting trips when you use a bore sighter.

Adjusting Hunting Rifle Scopes Using a Bore Sighter

The hunter, curled fetuslike, presses down into the Space
Blanket that serves to separate him from the damp
depression overlooking the field. It’s two hours into his
third and final day. The expectation that once helped keep
him still and silent, the absolute belief in deer,
has long gone. Nothing supports him in the face of
stiffness and cold, nothing fights off the nagging whispers
that say “quit,” or “for God’s sake, at least stand and
stretch” — nothing but the grim determination to go
out doing this right, to give no aid to an unfriendly fate.

Three hours. His body heat has melted the snow; wet fingers
stretch over the lip of the ground cover. He closes his
eyes against the internal taunts. When he opens them, three
bucks are walking stiff-legged into the field, a scant 100
yards distant.

No trouble with control now. The gun comes up to rest on
bent knees. A deep breath as the scope fills with deer, a
half breath out; the crosshairs drop and hold behind the
shoulder of the biggest, rest steady as the trigger creeps
toward the always surprising shot. There!

But the buck isn’t down. The trio mill about in brief
confusion and then stretch toward a windrow of trees. He
sweeps the scope with them, less steady now, but still
vacillating within the area of clean kill. A second shot.
No tail drop, no sudden stumble or twitch, no sound of a
bullet strike.

He’s on his feet now, aiming only at the middle of the big
buck’s body. Shot. Shot. Shot. And the snicker of a firing
pin on an empty chamber. Loading on the run, he finds the
deep-driven tracks of panic, follows them to the woods. No
blood, no hair. Five misses?

A shell in the chamber, past believing anything now, he
takes a careful rest and aims at a stump-center knot 30
yards off. Steady, squeeze, and bark jumps a full six
inches high, three to the right. He looks down at the
expensive rifle, feeling betrayal and the slow spread of
guilt.

It was spot-on last season.

Inciting a Sight-In

Missed shots or, worse yet, poor shots that result in the
escape of a badly wounded animal can often be traced to
either improperly sighted rifles or firearms that have had
their sights jarred out of adjustment. Of course, the
major cause of poor shooting is a shortage of
hunter ability; no scope, regardless of how well it’s
sighted-in, will compensate for a lack of familiarity with
the gun. The answer here is to practice, and then practice
some more.

On the other hand, a scope that’s out of adjustment can
frustrate the most experienced marksman. So take the time
to check a sighted-in rifle before each hunting
season (and then practice with it); do the same after
traveling to a distant hunt, or after a day in steep or
brushy country that could leave your rifle feeling the same
sort of knocks that can make a quiet evening in camp seem
like a little bit of heaven. More important still, never
assume that a newly purchased gun is right, whether bought
used or set up by sporting-goods store staff: You owe it to
yourself, and to the game you intend to hunt, to burn
enough powder to assure yourself that the job has been done
correctly.

Begin With a Bore Sighter

Although it’s possible to do the job without a bore
sighter, I’ve come to consider this tool (see Figure 2 in the image gallery)
indispensable when setting up a scoped firearm. This device
allows the rifleman, without even loading a shell, to align
the scope with the bore of the rifle. A bore-sighted firearm
will typically be “on the paper”–that is, it should
hit somewhere on a standard-sized rifle
target–at 100 yards. This can save a number of spent
shells during the adjustment process. It is, however, only
a preparation for final zeroing in.

To use a bore sighter, simply insert the appropriate rod
(several will come with the tool) into the muzzle of your
firearm, adjust the device until the calibrated lens is
centered in front of the rifle scope, then secure the bore
sighter in position by turning the knurled-head fitting to
expand the rod within the bore. Now look through the scope
toward a bright window or other source of light. The
calibrations on the bore sighter will be superimposed over
the crosshairs of the scope (see Figure 1 in the image gallery). Simply adjust the
scope until its crosshairs are centered on the bore
sighter’s checkerboard, and you’ll have taken a giant step
toward straighter shooting .

The final stage of the sighting-in process can best be
accomplished at a rifle range equipped with benches and
good gun rests. Failing that, make up a few small cloth
bags (about six inches square), stuff them with sand and
use them to rest the rifle on while shooting.

Set up a target at 100 yards if you’re sighting-in a deer
rifle, or at 50 yards if you’re using a .22. (If you’re not
at a range, make absolutely certain that you’ve got a
completelysafe backdrop behind your
target, such as a high, thick dirt bank.) Then —
wearing ear and eye protection — rest the gun
securely and squeeze off three careful shots at the center
of the target. The bullet holes should group at some point
on the target paper (see Figure 3 in the image gallery). Measure the distance from the
middle of your grouping to the bull’s eye, figuring first
the distance to the right or left of the target center
(windage) and then that above or below the bull
(elevation). Now adjust your sight or scope to compensate
for the error. To do so, you’ll have to know how the
calibrations on the sight work. Many scopes adjust in
clicks, each one equaling a change in point of impact of
one inch at 100 yards. With the adjustment made, take
another three careful shots. Your group should now be
closer to the bull’s eye. If it’s not close enough to suit
you, repeat the measurement, adjustment and
three-shot-group process as many times as necessary; that
is, until the rifle is dead-on.

(Note: Many hunters sight-in deer rifles to shoot about two
inches high at 100 yards, thus enabling the shooter to keep
the impact point within a clean kill zone at longer ranges
without having to aim high to account for bullet drop.
Before doing this, check the ballistics of your
rifle-and-cartridge combination — most any gun-shop
owner will have a chart — to determine how far you
can expect the point of impact to change over a given
distance.)

Once carefully sighted-in, your rifle will give you the
best it’s capable of. Your next step is to get in enough
shooting time with the firearm, at various distances and
from sitting, prone and offhand (standing) positions, to
make sure that you’re able to contribute an equal (well,
nearly so) ability. With that done, you can take to the
field with calm confidence, which is probably the most
important hunting tool of all.