The H&R M16A1 Semi Automatic Rifle features a Pencil Barrel made from 4150 Chrome Moly Vanadium Steel with a parkerized finish and chrome lining. Features a Rifle Barrel Extension, 1/2X28 threaded barrel, 1/12 twist rate, and a Rifle gas system. Upper: Newly manufactured uppers forged from 7075-T6 Aluminum using proprietary NoDak Spud Dies. Finished in black anodizing. Lower: Made from forged aluminum and equipped with the Retro H&R FCG and A1 furniture, this lower is classic in style and performs like an American Classic should. FeaturesM16A1 Upper Receiver without Feed RampsM16A1 Triangular Handguard with Heat Shields1:12" Twist Rate1/2X28 Thread Pitch