How to Boresight a Rifle

When you purchase a new optic for your rifle, that optic is not going to be accurate right out of the box. Before depending on your optic to help you hit exactly where you mean, you’ll have to zero it. Sighting in your scope can take a long time and waste a lot of ammo. Fortunately, there is a solution.

There is a more efficient and faster way of zeroing in a new optic. By using a laser boresight, you save time and money by making sighting-in much faster without using any ammo!

Bore sighting is a reliable way to align your reticle, sights and scope’s crosshairs with the true center of the gun’s barrel—which is the bore. Boresights use a laser diode to project a dot on a target much like a laser pointer, making it easy to see when your crosshairs align with the laser. Since the two run parallel to each other, they can only truly zero at a given distance. This is typically 25 yards.

You can bore sight any firearm—AR-15 and other MSWs, shotgun, bolt-action, and handguns. Bore sighting also works on any sighting system—red dot, reflex, riflescopes, holograph and even your iron or night sights.

There are two different types of laser boresights—one you put directly into the chamber and one you insert into the barrel.

In-Chamber

In-chamber boresights are inserted directly into your gun’s chamber, so they must be caliber-specific and made to the same dimensions and specs as a cartridge in that caliber. These types of boresights are the most accurate. These can, however, become costly If you have firearms in multiple calibers that you need to sight in, because you must purchase a separate boresight for each caliber.

Laser boresight cartridges are easy to use. You simply turn them on and insert it into the chamber of your firearm like you would a live round or snap cap.

Sightmark in-chamber boresights are superior to competitors, due to the multiple set screws that lock in the laser diode, ensuring the laser stays straight and centered. To test an in-chamber boresight’s accuracy, roll your laser boresight on a flat surface, the laser should stay straight along the wall as you roll it. If the dot rotates, you know the diode is canted and you won’t be able to accurately zero-in your scope.

Made of high-quality brass, the Sightmark boresights are calibrated to make sure the laser is true to center, and measure precisely the same specs as a live round. The extensive offerings include 12- and 20-gauge shotgun, the most popular self-defense handgun calibers, and over 30 different hunting, defense, sporting, and popular rifle calibers—including .223/5.56, .308, .50, .300 BLK and 6.5 Creedmoor.

Using an In-Chamber Boresight

1. Use a benchrest, shooting bags, or another platform that stabilizes your gun. Make sure the firearm is completely unloaded and pointed in a safe direction.
2. Hang a target 15 to 25 yards out.
3. Remove the batteries from the boresight packaging and unscrew the bottom of the boresight. Insert the two batteries according to the instructions. The boresight will automatically turn on when the batteries are inserted correctly.
4. Lock your bolt open to the rear.
5. Put the laser boresight into the chamber.
6. You may close the bolt or leave it open.
7. Line the laser beam on to the center of the target.
8. Look through your optic and using your windage and elevation knobs, adjust the reticle, dot or crosshairs until it lines up with the dot of the laser boresight.

Universal Boresights

Other boresights are either attached or inserted into the barrel. Most boresights that you must insert into the barrel come with a set of arbors that will modify the boresight to fit different barrel sizes. These types of boresights are the most affordable, but they do come with some disadvantages.

• Arbors are small and can get lost easily. They also wear out and break.
• The entire boresight itself can play against the barrel, causing inaccuracy.
• Safety concerns. Forgetting to remove a boresight from the barrel can result in a catastrophic accident.

Sightmark’s universal boresights provide a much safer way to boresight if you prefer this type of boresight over an in-chamber boresighter. If you have looked at any firearm failure montages or spent any good deal of time on gun blogs and forums, you have probably seen the blown-up barrel caused by an in-barrel boresight. Our universal laser boresights securely stay on your rifle, shotgun, or pistol via a heavy-duty magnet. Only a small portion of the arbor goes inside the barrel. They incorporate a self-centering arbor, so you never have to worry about losing pieces or breaking parts. They will sight in firearms .17 to .50 caliber.

Using the Universal Boresight and Universal Boresight Pro

1. Use a benchrest, shooting bags, or another platform that stabilizes your gun. Make sure the firearm is completely unloaded and point it in a safe direction.
2. Hang a target 15 to 25 yards out.
3. Remove the Universal Boresight from the package. Turn the unit on. To preserve battery life, the Universal Boresight Pro will only activate when the arbor is pressed in when it is attached to the barrel.
4. Remove any suppressor or muzzle device you have on your firearm.
5. Simply attach the boresight to the end of the barrel.
6. Look through your optic and using your windage and elevation knobs, adjust the reticle, dot or crosshairs until it lines up with the dot of the laser boresight.

It’s as easy as that!

Now, you are ready to head to the range to make precise adjustments to your riflescope. It shouldn’t take but a few rounds to zero it in.

You will want to bore sight your firearm any time you get a new optic, upgrade factory sights, for a competition, before hunting, and on a firearm that has been in storage.

Click here to buy boresights from Sightmark.

Do you have questions about boresights? Leave them below and we will do our best to answer them.