Barrel: Chrome-moly vanadium steel barrel chambered in 5.56 NATO, with a 1:7 twist rate, M4 barrel extension, and a carbine-length gas system. M4 profile barrel is finished off with a 13.5" PSA Lightweight M-Lok free-float handguard, low-profile gas block, and A2 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 Carrier Group: Full-auto profile bolt carrier group. Shot-peened, mil-spec Carpenter 158 steel bolt. Gas Key Hardened to USGI Specifications, fastened with Grade 8 screws, and Staked Per Mil-Spec. Carrier is 8620 steel M-16 full auto profile and is chrome lined and phosphate coated. Lower: These forged lowers are quality made using 7075-T6 aluminum and are marked "MULTI" for the caliber. Finish is hard-coat anodized. The Mil-spec diameter 7075-T6 buffer tube is hard-coat anodized, has 6 adjustment positions, and is fitted with a PSA Classic Carbine Stock for a traditional AR-15 look and feel. The rifle is finished off with a PSA Classic A2 grip, and standard Mil-Spec AR-15 Fire Control Group.