US Patent 9170079 Laser trainer cartridge

A cartridge laser trainer fits into a gun barrel and includes a backer, circuit and a laser. When the firing pin of the gun is activated it strikes the backer, which contacts the circuit and activates the laser. The cartridge laser trainer may also have one or more O-rings to keep it positioned properly in the gun barrel. Also disclosed are kits that contain (1) a plurality of sheaths and a cartridge laser trainer, or (2) a plurality of O-rings and a cartridge laser trainer. Each sheath or O-ring(s) is configured to be positioned in a particular-sized gun bore and is configured to receive a cartridge laser trainer. With a kit, a single cartridge laser trainer can be used with more than one size of gun bore.