Originally Posted by crimdelacrim
you mean F.A.'s made before 1986? Because I made sure I mentioned modern full autos in my post but ill edit it
The answer is: same reason you have to have a tax stamp for a silencer/suppressor or a short barrelled shotgun and the same reason switchbaldes are illegal or regulated in most states - the people who make laws learn all they know about crime and reality from television/movies and those are the things that look scary in movies.