A boresighter is a device used to align the sights or scope of a hunting firearm to it’s bore. It’s primary use is to ensure a hunter is able to set the sights or scope so the gun prints on paper on the first shot, reducing the amount of ammunition expended during the sight-in process. This is an important consideration, especially when using today’s expensive premium hunting ammunition. A secondary use is for checking the zero of a firearm while in the hunting field at any time without firing a shot.
Boresighters come in two styles. The first has a collimator, which depending on the model, attaches to the muzzle of the gun with either a magnet or an arbor. The magnet-mount type can be used for all firearms regardless of caliber or barrel length. The arbor type will come with arbors for calibers from 22 to 45. The gun must have a barrel length of at least 4 inches. Once attached to the firearm, the reticle or sights need to be adjusted until they point to the middle of the grid pattern. This will ensure that the sights are aligned with the bore, thus the first shot can be expected to strike close to the bullseye of the target. After final sight-in, reattach the boresighter and make a record of the position of the sights or scope reticle to check the zero at a later time, such as during a hunting trip where firing a shot may alert nearby game.
The battery operated laser boresighter is the second style of boresighter. They come in two types. The first, being made of brass with the same dimensions as a cartridge case, fits into the chamber or cylinder of a firearm and will project a laser beam through the center of the bore onto the target. Once the scope or sights are adjusted to the point of the laser spot, the firearm can be expected to strike the target on the first shot. These boresighters can be used at any distance between 15 and 100 yards and are available for rifle and handgun hunting cartridges from 17 HMR to 416 Remington Magnum and also 20 and 12 gauges, with all barrel lengths. Aimshot and NC Star are two manufacturers that produce this style.
The other style of laser boresighter is made to insert into the muzzle of a firearm. Adapters are made for calibers from 17 to 75 plus 12 and 20 gauge shotguns and requires a minimum barrel length of 4 inches. Once tightened for a snug fit, it will project a laser beam onto a target, as an extension of the firearm’s bore. Two makers of this type are Bushnell and Laserlyte. They can be used for distances from 10 to 100 yards.
After the gun is zeroed, a laser boresighter can also be used to check the zero at any time without firing a shot. The results will be more precise than with the collimator-type boresighters. Place a target at a specific distance, such as 50 yards, and mark where the sights and laser are in relation to each other. To check the zero afterwards, use the same target placed at the same distance to verify that the relationship has remained the same.
Regardless of which boresighter you choose for sighting-in your hunting guns, they will all to do what they are made for. One of the laser boresighters may be a better choice if accurate zero checking is a priority, or if using open sights. Otherwise, selection may be just a matter of personal choice.