Hey all, I am very interested in building an AR or AK pistol. I have built a few AKs, and I know that many people say "it has to be a virgin receiver registered as a pistol" Is this true?? Where does it state in the law?? I think I will email the ATF. I was just thinking about other guns that can be either a pistol or a rifle like the TC contender or encore. I had one of these guns. It didn't matter whether it was registered as a pistol or a rifle. You could easily swap it out for either one. Why are AR's or AK's any different??? Thanks for the imput!