BSF Barrels AR-10 Barrel 6.5 Creedmoor 14.5" 1:8" Twist Carbon Fiber. This carbon fiber wrapped barrel is designed to move heat with the barrel and vent heat quickly thanks to strategically placed slots in the carbon fiber. Built with a 14.5 inch length and a 1:8 twist rate for stable performance with 6.5 Creedmoor ammunition. The barrel features 5/8x24 threading for muzzle devices. The carbon fiber wrap is designed to improve heat management while maintaining barrel strength.