Easy-to-use, self-contained boresighting system fits in the chamber of your rifle or pistol and projects a powerful red laser beam aligned with the bore axis for sighting to the point-of-aim without firing a shot. Works with scopes, holographic red dot sights, and “iron” sights. Durable, machined brass housing looks like a cartridge case but actually contains the entire laser system and batteries. Insert the batteries and screw the cap on the housing to turn on the laser; remove the batteries to turn off. Insert the entire assembly into the chamber, gently close the action, and aim at a target 20-30 yards away. Adjust windage and elevation of the scope or sights so point-of-aim is zeroed on the dot, compensating for sight offset to prevent gun from shooting high. Go to the range for test shots and final sight adjustments. Store boresighter in the included nylon carrying case that fits easily in a pocket, tool kit, or range bag. Available in a variety of calibers, listed below.