Boresighters

Boresighting is a method of adjustment to an optical firearm sight or iron sight, to align the firearm barrel and sights. This method is usually used to pre-align the sights which makes zeroing much faster. The process can be completed with naked eye, or with a specialized device called boresighter. It consists of an optical head and a bore-diameter arbor which is inserted into the muzzle of the rifle. The optical head is then attached to the protruding end of the rod. A grid pattern on the optical head is then used to align the sights with the barrel.

There are two different boresighting, which is Optical Boresighting and Laser Boresighting. Optical Boresighting is a traditional boresighting involves removing the bolt and exposing the breech, then sighting down the bore of the gun to a fixed point. Whereas, Laser Boresighting is a modern method of boresighting by using a laser pointer rather then by vidual inspection to illuminate the distant point of aim. This is method is preferable because it allows more movement in the gun, as the laser dot will not move relative to the barrel, and is a method of boresighting which does not require the removal of the bolt.