Barring All Guns • 101 Th/s prison-made break-top-type .4 1 0-gauge shotgun was fired by pulling back on the spring and releasing. (Courtesy of Clair F. Rees) As most any prison-knowledgeable person will tell you, the majority of illegal weapons held by prisoners are strictly for defensive purposes. The majority are small, homemade knives, but homemade guns are not uncommon. Every month, in prisons all over the world, zip guns turn