Barrel: 416R Stainless steel. Chambered in 6.5 Grendel, with a 1:8 twist, M4 barrel extension, and a carbine-length gas system. The barrel is finished off with a PSA 12" Slanted M-Lok free float rail, .750 adjustable gas block, and A2 flash hider. Upper: Forged 7075-T6 A3 AR upper is machined to MIL-SPECS and hard coat anodized. These uppers are made for us right here in the USA by a mil-spec manufacturer. Bolt: Full-auto profile bolt carrier group. 9310 steel bolt, Shot Peened, Gas Key Hardened to USGI Specifications, Fastened with Grade 8 screws, and Staked Per Mil-Spec. 8620 steel M-16 profile carrier is nitride treated.#html-body [data-pb-style="62DF8287D84B2"]{justify-content: flex-start; display: flex; flex-direction: column; background-position: left top; background-size: cover; background-repeat: no-repeat; background-attachment: scroll; border-style: none; border-width: 1px; border-radius: 0px; margin: 0px 0px 10px; padding: 10px;}#html-body [data-pb-style="62DF8287D84BF"]{border-style: none; border-width: 1px; border-radius: 0px; margin: 0px; padding: 0px;}