Barrel: 8.5" 4150V Chrome Moly vanadium steel is chambered in 300 Blackout with a 1 in 7" twist. The Nitride pistol-length gas barrel is finished off with a PSA 10.5" Lightweight Hex M-Lok Rail, a .750 low profile gas block, and an A2 Flash Hider Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized black for durability. Featuring a mil-spec finish, these uppers are made for us right here in the USA by a mil-spec manufacturer.