One can probably be picked up from an army surplus warehouse somewhere in the former Soviet Union/(some current conflict zone), for an ~$X,000 USD bribe, or alternatively, manufactured by a literate, mildly motivated individual with a high tolerance for personal risk, a welder, a lathe, a tool-shed, and an outhouse in the mountains.
Given that we live in a world where gunpowder has been invented, you will have to pardon me if I'm more concerned about the dangers of lunatics with mundane explosives, and delivery systems thereof.