Barrel: 10.5" Chrome Moly vanadium steel, nitride treated for durability and chambered in 300AAC Blackout with a 1 in 8" twist rate. pistol-length gas barrel is finished off with aPSA 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.