Pictured are two dirt simple improvised ‘zip guns’ seized by police which were the subject of an officer safety notice. The weapons have been constructed by screwing together standard pipe fittings which can be obtained for a total of around $5 at any local hardware store. Each gun consists of a length of copper pipe threaded on both ends, a brass hose nipple (which functions as a barrel), a length of wire rope attached to a makeshift firing pin, a compression spring, an end cap drilled in the center and a ring which serves as a charging handle for the striker assembly.

Disassembled zip gun consisting of striker assembly, copper tube, .22lr round and hose nipple barrel.

To fire the weapon a .22 round is inserted into the brass hose fitting which is then screwed onto the copper pipe. When ready to fire, the ring is pulled to the rear which compresses the spring against the striker. Releasing the pull ring drives the striker forward, striking the rim of the cartridge and firing the bullet out of the tiny barrel. Weapons such as these are typically found in use by outlaw motorcycle gangs owing to their ability to be disassembled and remain undetected during a cursory search of a toolbox or holdall. Small caliber firearms using the same striker mechanism have in the past even been seen skillfully machined to resemble large diameter bolts with this in mind.