US Patent 10317172 In-chamber laser boresight device

A boresight device includes a casing designed to be loaded into a chamber of a firearm in the place of a bolt carrier group. The casing may include one or more keyed features to engage with corresponding components of the firearm such that the one or more keyed features align an exit port in the casing to a barrel of the firearm upon loading of the casing into the chamber. The boresight device may further include a laser device for generating a laser beam. The laser device is positioned within the casing to direct the laser beam through the exit port of the casing and along an axis of the barrel when the casing is loaded into the chamber.