If you haven't heard, Sig Sauer is making a new carbine in 9mm, .40S&W, and .357 Sig. It has a 6.5 in barrel with a 9.5 in muzzlebrake. The muzzle brake is baffle system used in a suppressor. What I am wondering is what type of paperwork and transfer would be involved in that? You only buy a metal tube and an end cap but it suppresses the weapon. I'm a loss here, and I really want an MPX-C and I want to suppress it since it is so cheap to do. Does anyone know what type of taxes and paperwork would go along with that?