This Bear Creek Arsenal AR-15 20" heavy black nitride 5.56 barrel, has a rifle length gas system with a 1:7 twist.The 5.56 NATO black nitride finished barrels are made from the finest 4150 Chrome Moly Vanadium and precisely rifled for high accuracy at a great price. Use a Bear Creek Arsenal ar barrel in your next AR 15 build and experience superior performance back by a lifetime warranty!All finished barrels go through a 100% inspection process. Inspections Equipment includes CMMs and Air Gauges for the bores as well as visual and machine inspection.We are an approved Bear Creek Arsenal dealer. To bring you the lowest prices, this auction item may be ordered upon a placed bid, which may add 5 business days to our regular shipping schedule.Specifications:Weight (lbs): 3.39Magazine Capacity: N/ALength: 20Profile: Heavy BarrelTwist: 1:7Finish: Black NitrideMaterial: 4150 Chrome Moly VanadiumThread Pitch: 1/2 x 28Caliber: 5.56 NATOFeed Ramp: M4 FeedrampFlutes: NoneGas System: RifleGas Block System: 0.750Classification: BarrelPlatform: AR-15