Bore sighting a rifle aligns the bore to the reticle of the scope. It accurately sights the rifle by matching regular rifle sighting to mounted scope sighting. Once your rifle is bore sighted, it will be sighted in accurately, whether or not the scope is on.
Bore sighting is essential before you zero your rifle at the range.
Before you engage in bore sighting your rifle, ensure your rifle is unloaded, the safety is on and the rifle is clear of ammunition.
Mount the Scope
If you haven’t mounted a scope on your rifle, you’ll need to do so by installing scope mounts.
Your rifle, if it’s a modern rifle, will have screw holes pre-drilled and tapped for scope mount installation. Use these screw holes, install mounts and ensure they’re secure.
Install scope rings on the scope. These rings need to be sufficiently loose for you to be able to rotate the scope and move it backwards and forwards after the scope is mounted.
Adjust the scope till the horizontal line on the reticle is level.
Adjust the eye relief on the scope and ensure that there’s enough eye relief so the scope won’t make contact with your face on recoil.
With the gun in a comfortable shooting position, position the scope by moving it forward or backward. You want to ensure there’s no black ring around the objective.
After you have mounted your optic to your rifle, bore sighting can commence.
Bore Sighting without a Bore Sighting Device
Create a target that’s very specific with high contrast. The target must be clearly visible with both kinds of sights. A bright red dot is good. The target should be around 100 yards (91.4 m) away for optimum sighting.
There are two methods to bore sight without a bore sighting device.
Find the Mechanical Center
Find the middle of the scope’s mechanical adjustment range so the scope has its full range in all directions.
Turn the windage turret all the way in one direction.
Now turn the windage turret in the opposite direction while counting the revolutions as you turn.
Dial the turret halfway back to the middle.
Do the exact same thing on the elevation turret.
The optic should now be at the center of its mechanical adjustment range.
Some people prefer to ‘center’ the reticle lower for more upward travel in the optic for long distance targets. The type of shooting you intend doing will influence your notion of ‘center’.
Sight in the rifle at the gun range. Go through a few practise rounds to get the feel of the scope and make small adjustments as necessary.
Look through the Bore
Line up the front sight by looking through the bore and aligning it with the center of a distant target.
Using a gun vice or a bench or other stabilizer to keep the gun level, make adjustments.
Obtain a good sight picture with the front sight.
Line up the cross-hairs on the scope with the target. Ensure that you keep a good sight picture. Keep your eye at the appropriate distance from the scope.
To line up the scope as accurately as possible, look through the optic and adjust the turrets to align with the center of the same distant target you saw through the bore. Adjust the elevation and windage on the scope as necessary.
Look through the end sight at the appropriate cheek-weld and sight picture, while simultaneously looking through the scope at the appropriate distance.
Both views need to be lined up with the exact same spot. A gun vice or other secure stabilizer makes adjustment doable without holding or moving the gun.
Sight in the rifle at the gun range. Go through a few practice rounds to get the feel of the scope and make small adjustments as necessary.
Bore Sighting with a Bore Sighting Device
Read the device’s manual to ensure you use it correctly.
Carefully insert the arbor into the bore. Be careful not to damage the crown or the rifling.
Remove the bore sighter when you’re finished bore sighting.
This is a device that’s inserted into the muzzle end of the barrel. It uses a reflective surface and lenses to replicate a target.
When you look through the optic, there’s a target-like grid.
You need to get the optic’s reticle to align with the collimator’s center. Do this by turning the windage and elevation turrets.
If you have to adjust more than 6-8 inches to align the reticle with the collimator’s center, there’s possibly an issue with your optic’s mounting. Check and correct the mounting.
Laser Bore Sighter
Visual bore sighting can get you on paper at 100 yards, but laser bore sighting gets you much closer to center. It also requires less ammunition in the long run when zeroing the rifle.
Some laser bore sighters are inserted into the muzzle end of the barrel, while others are placed in the rifle’s chamber like a dummy round.
Laser bore sighters emit a laser, which should be pointed at a target about 25 yards away in a safe direction.
Fit the laser unit into the barrel of an unloaded gun and turn on the laser. There’s usually a rotating knob on the body of the bore sighting device to turn it on.
Position the gun so that the laser dot is centered on the target. The ambient light of morning or evening is better because the red laser dot can be lost in bright sunlight.
Looking through the optic, turn the windage and elevation turrets so the optic’s reticle aligns with the laser. Move the reticle’s adjustment turrets until the center overlaps with the laser dot on the target.
If you have to adjust more than 6-8 inches, check the optic’s mounting.
Remove the laser device from the barrel. This is important.
Move the target to 100 yards.
Commence zeroing in with live ammunition.
Companies like LaserLyte offer laser bore sighting devices and bore sighting kits.
Bore sighting is a simple way to save time and money and get your gun on target before you ever fire a shot.