RF85 Treated Anderson 7.5” 300 Blackout Complete Upper With EXT Forearm, 7.5” 300 Blackout Contour Barrel. 1-7 twist. Phosphate Finish, Pistol Gas Set Up, 5/8-24 threads, Forged Upper Receiver, Anderson EXT Hand Guard Pistol Length, Knight Stalker Flash Hider, M16 Carrier is Chrome Lined, made from 8620 steel, Bolt is made from 9310 steel and coated per mil spec. MPI Tested. The 223 Bolt and Bolt Carrier Assembly comes complete with Cam Pin, Firing Pin and Firing Pin Retainer and Standard Charging Handle.