Barrel: 7.5" 4150V Chrome Moly Vanadium steel, nitride coated and chambered in 5.56 NATO with a 1 in 7" twist. Pistol-length gas barrel is finished off with a PSA 7" Lightweight M-Lok Rail, a 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. Bolt: Bolt is made of Mil-spec shot-peened Carpenter 158 steel. Gas key is secured with grade 8 fasteners and staked per mil-spec.