Then just submit SBR paperwork and $200 and 8 months later you can put on a proper rifle stock. Beautiful.Nice compact AR15 pistol for less than $500:
Upper with KAK flash can - $240 - http://palmettostatearmory.com/psa-7-nitride-5-56-1-7-with-7-2a-armament-mlok-and-kak-flash-can-no-bcg-or-charging-handle-516445150.html
Pistol Magpul lower - $140 - http://palmettostatearmory.com/psa-complete-moe-pistol-lower-receiver-black.html
BCG/CH - $90 - http://palmettostatearmory.com/psa-5-56-premium-full-auto-bolt-carrier-group-psa-ar15-m16-7075-t6-forged-mil-spec-charging-handle.html
Cheap ($8.5) to free shipping then $15 for FFL fee = less than $500. Good deal IMO.