While at Code 4 Arms we DO sell NFA Firearms (Short Barrel Rifles, Short Barrel Shotguns, Suppressors (or, if you must, silencers) and the occasional Automatic Weapon, we generally only sell them to Law Enforcement Agencies.  That being said, it IS possible for civilians to purchase NFA items, but the cost (both of the firearm itself AND the SOT License required to own an NFA weapon or accessory) typically makes it too expensive to make sense.  Additionally, there are still Federal and State regulations which limit WHAT a civilian can own, even with an SOT.