The Sentinel 8.6 BLK, part of Faxon's Summit Line of firearms, boasts a billet aluminum receiver set, G3 Aluminum Streamline M-LOK Handguard, new 8.6 BLK MuzzLokA(R) Muzzle Device, and the impressive 1:3 twist Modified Big Gunner Profile Barrel. The Faxon Sentinel is backed by Faxon's Lifetime Guarantee.Faxon Sentinel in 8.6 BLK rifles are optimized for supersonic ammunition. Use of subsonic ammunition may require adjustment to rifle for optimal performance. Features7075 Billet Aluminum Receiver SetFaxon 16" 1:3 Twist Big Gunner Profile 8.6 BLK Barrel4150 CMV, NitridedFaxon MuzzLokA(R) 8.6 BLK 3-Port Muzzle BrakeFaxon G3 Aluminum Streamline M-LOK HandguardFaxon G2 Superfinished AR-10 BCGFaxon AR-10 Height Gas BlockB5 Precision Collapsible StockFaxon Trigger by Rise ArmamentB5 Pistol GripAmbi Charging HandleAmbi Safety SelectorCarbine-Length Gas System