This 20 by 6MM ARC DMR rifle length barrel is machined from 416 stainless steel with a QPQ finish. Premium Black Series barrels feature a Nickel Boron coated Extended M4 feed ramp extension. Includes pinned front sight base (FSB). Rifle-length gas system, 1/7 twist, .750 gas block journal, and 5/8x24 muzzle threads. Weight 46.2 oz. Profile: DMR. Length: 20. Finish: QPQ corrosion resistant.