CMMG Barrel Sub-Assembly Features The CMMG Barrel Sub-Assembly is purpose built to bring Hornady s 6mm ARC cartridge to the AR-15 platform giving builders a dedicated barrel rather than trying to adapt a different chambering. Machined from 416 stainless steel the barrel offers strong corrosion resistance and the machinability needed for tight consistent chambering tolerances. A medium taper profile balances weight and rigidity keeping the barrel light enough for maneuverability while remaining stiff enough for consistent accuracy. The 1:7.5 twist rate is matched to the heavier higher ballistic coefficient bullets that 6mm ARC shooters commonly run for long range performance. At 16.10 in a rifle length configuration this barrel sub-assembly threads 5/8-24 tpi ready to accept a suppressor or muzzle brake for reduced recoil and improved control. A black nitride finish provides lasting protection against the elements and the wear of repeated firing cycles. This barrel ships without sights giving builders a clean slate to add their own optic or iron sight setup suited to their build. For AR-15 owners looking to add a dedicated 6mm ARC barrel CMMG s sub-assembly provides a direct path to that chambering without reinventing the rest of the rifle. CMMG Barrel Sub-Assembly Specifications Manufacturer: CMMG Model: Barrel Sub-Assembly Caliber: 6mm ARC Barrel Length: 16.1 Twist Rate: 1:7.5 Material: 416 Stainless Steel Finish: Black Nitride Barrel Type: Rifle Length Thread Pattern: 5/8x24 Compatible Hosts: AR-15 Available At: GrabAGun