Barrel: 10.5" Chrome Moly vanadium steel, nitride coated and chambered in 5.56 NATO with a 1 in 7" twist rate. The carbine-length gas barrel is finished with a PSA 9" Lightweight Hex Full Picatinny M-Lok Free Float Rail, a low profile gas block, and an A2 Style Flash hider. Upper: Forged 7075-T6 A3 AR upper is made to MIL-SPECS and hard coat anodized black for durability. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt: The bolt is made of Mil-spec shot-peened Carpenter 158 steel and the gas key is secured with grade 8 fasteners and staked per mil-spec. The bolt carrier is 8620 Steel.