This is an area I have never understood. The way it was always explained to me, including by ATF agents, is that the suppressor itself is registered as the "firearm", however, I can walk into Walmart right now, and buy a suppressed air rifle without any kind of paperwork. If a suppressor is a suppressor is a suppressor, regardless of what it's mounted on, or even if not mounted, then how exactly are these legal? Don't get me wrong, I am always for fewer restrictions, especially when they are on a safety device made to protect our hearing, and think there should be no restrictions on suppressors for any of us, but have always been of the belief that I would much rather complain about BS laws from outside a jail cell, than inside.