Features Barrel: Chrome-moly vanadium steel barrel chambered in 300 Blackout, with a 1:7 twist rate, M4 barrel extension, and a pistol-length gas system. The nitrided barrel is finished off with a 4" knurled tube free-float handguard, R-marked front sight gas block, and an A2 flash hider. Upper: Forged 7075-T6 C7 AR upper is machined to MIL-SPECS and hard coat anodized. Uppers include forward assist, dust cover, and A1 rear sight appature. 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. Details Barrel Length: 7.5" Barrel Material: 4150V Chrome Moly Vanadium Steel Barrel Finish: Nitride Barrel Profile: Heavy Chamber: 300AAC Blackout Twist Rate: 1 in 7" Extension: M4 Gas System: Pistol-Length Gas Block Type: .750 R-marked FSB Upper Receiver: Forged 7075 T6 Aluminum Receiver Style: C7 Carry Handle Receiver Finish: Hardcoat Anodized Forward Assist: Yes Dust Cover: Yes Handguard Style: DPMS 4" Knurled Tube Bolt Steel: Carpenter 158, Mag Phosphate coated Bolt Carrier Steel: 8620, Chrome Lined Staked Gas Key: Yes