CMMG AR Barrel Sub-Assembly Features The CMMG Barrel for 8.6 Blackout is machined from 4140 chromoly steel a material selected for its strength and ability to hold up under the pressures generated by heavy-bullet big-bore cartridges. A black nitride finish coats the barrel offering corrosion resistance along with a clean modern appearance that matches other nitride-finished CMMG components. The barrel s fast 1:3 twist rate is specifically suited to stabilizing the longer heavier bullets that 8.6 Blackout fires a critical factor for maintaining accuracy with this cartridge at various distances. Cut to 12.5 inches in length the barrel balances a usable sight radius with a compact overall rifle length suited to close to mid range use. Designed to accept 0.750 inch diameter gas blocks the barrel fits a common gas block standard that simplifies parts sourcing for builders assembling a complete upper. A 5/8x24 thread pattern at the muzzle is standard for this bore size giving builders access to a wide range of muzzle devices and suppressors rated for the cartridge s pressure and recoil characteristics. This barrel is compatible with CMMG Mk3 and DPMS Gen 1 high-pattern LR-308 upper receivers giving builders a known-fit starting point for an 8.6 Blackout build. At 1.85 pounds the barrel adds meaningful heft appropriate to the cartridge it is chambered for for sale at GrabAGun. CMMG AR Barrel Sub-Assembly Specifications Manufacturer: CMMG Model: Barrel Sub-Assembly Type: Rifle Barrel Caliber: 8.6 Blackout Barrel Length: 12.5 Color: Black Material: 4140 Chromoly Steel Finish: Nitride Twist Rate: 1:3 Thread Pattern: 5/8x24 Weight: 1.85 lbs Available At: GrabAGun