Designed using precision engineering adopted from the aerospace industry, Christensen Arms carbon-fiber barrels are crafted using a proprietary layered design that offers any marksman superior accuracy and performance. The barrel lining is made from match-grade 416R stainless steel and is measured to a tolerance of +/- .0001. When it comes to accuracy, Christensen Arms carbon-fiber barrels have performance you can trust. Includes gas block and gas tube. 18" Select Match Grade Barrel – Carbon Fiber wrappedCaliber – 6.5 Grendel 1-8 twistThread pattern – 5/8 – 24Gas Block – .938 ID 7075-t6 aluminumGas Tube – MIL-SPECBarrel Extension – MIL-SPEC18" Overall Weight – 1lbs 14oz