Faxon Firearms Duty Series Barrel Features The Faxon Firearms Duty Series Barrel uses the Gunner profile which keeps a Government-diameter contour from the extension back to the .625 gas block then tapers to a pencil profile from the gas block forward. That design pulls weight out of the front half of the barrel improving handling and reducing fatigue while keeping mass toward the rear for heat resistance and reduced barrel whip. Chambered in 5.56 NATO with a 1 in 8 twist the button rifled 4150 CMV steel barrel stabilizes a wide range of bullet weights. An 11 degree target crown protects the muzzle and helps preserve accuracy shot after shot. Manufactured entirely in-house in Cincinnati Ohio every Faxon barrel is stress relieved air-gauge tested and individually checked for headspace with precision gauges before it ships. The 12.5 barrel runs a mid length gas system which times gas pressure more evenly than a carbine length system for smoother cycling and less bolt bounce. Finished with a black nitride treatment both inside and out the barrel resists corrosion and wear while extending service life in the bore. With a 1/2x28 threaded muzzle ready for a brake or suppressor this Duty Series Barrel is built for shooters who want a reliable balanced upgrade for their AR-15. Faxon Firearms Duty Series Barrel Specifications Manufacturer: Faxon Firearms Model: Duty Series Barrel Type: AR Barrels Compatible Hosts: AR-15 Caliber: 5.56 Color: Black Material: 4150 CMV Steel Barrel Type: Button Rifled Barrel Profile: Gunner Barrel Length: 12.5 Twist Rate: 1:8 Gas System: Mid Length Thread Pattern: 1/2x28 Finish: Black Nitride Weight: 1.22 lbs Available At: GrabAGun