♪ homemade weapons the inmates have made from bed springs or melted down plastic. i mean, they're truly ingenious. but they're deadly, as well. >> at california's san quentin state prison, we saw how sophisticated some inmate weaponry can be. this homemade pistol is known as a zip gun. >> this portion is filled with ground up matchheads. the two holes here, inmates insert a wick. the inmate takes a plunger, pokes shrapnel in the open end, pieces of metal, ground up zippers. when the target walks by the cell, be it an officer or an inmate, the inmate lights this, it goes down, strikes the match heads, basically acts like a firecracker and shoots the shrapnel out. >> the majority of inmate manufactured weapons or shanks are designed for slashing or stabbing.