It's my understanding that it is illegal to own a shotgun or rifle with a barrel length less than 18". This information may or may not be correct. Assuming that it is, at what point does a rifle or shotgun become a handgun? I have seen many ruger 10/22s turned into pistols, and what about firearms like the XP-100 or the TC Contender? I'd like to buy a single shot .410 and rebuild it into a handgun, but I would also like clarification on the law. Thanks!