Barrel: 7" 4150V chrome moly steel. Chambered in 300 Blackout, with a 1:8 twist rate, M4 barrel extension, and a pistol-length gas system. The barrel is nitride treated and finished off with a PSA 6" Lightweight Hex Full Picatinny M-Lok Free Float Rail, a .750" low-profile gas block, and an A2 style flash hider. Upper: Forged 7075-T6 A3 AR upper is machined to MIL-SPECS and hard coat anodized. Uppers include forward assist and dust cover. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt: Full-auto profile bolt carrier group. Shot-peened, mil-spec Carpenter No. 158A(R) steel bolt. Gas Key Hardened to USGI Specifications, Fastened with Grade 8 screws, and Staked Per Mil-Spec.