Barrel: Chambered in 300AAC Blackout with a 1:7 twist rate, M4 barrel extension, and a pistol gas system this barrel features a nitride finish for accuracy and durability. It is finished off with a PSA 7" Lightweight M-Lok rail, .750" diameter 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 machined T marks, and a mil-spec finish. 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. Lower: This forged lower is quality made using 7075-T6 aluminum and is marked "MULTI" for caliber. The finish is hard coat anodized. Finished with an Magpul MOE Grip, H&R HAR-15 Adjustable Pistol Stabilizing Blade, and 6 position 7075 buffer tube. The fire control group is a PSA mil-spec finished, single-stage assembly.