Stainless accuracy with heavy barrel heat resistance and durability. QPQ Black Nitride for longevity, performance, and corrosion resistance. Faxon Firearms barrels are the pinnacle of value. Manufactured 100% in-house from cradle-to-grave, these barrels are fully stress relieved, air-gauge tested, and 11 degree target crowned to ensure superior accuracy. Quality is imbued into our barrels from the start. We start with the best materials, either certified 4150 Mil-Spec steel or 416-R Stainless. From there, each barrel goes through a battery of tests at each operation until finished in Nitride and final inspected. All barrels are individually checked for headspace by precision custom hardened gauges. Faxon manufactures all our barrels in Cincinnati, Ohio under our ISO:9001 and AS:9100 quality certifications. Barrel Material: 416R Barrel Type: Button Rifled Barrel Caliber: 5.56 NATO Barrel Twist: 1:8 Barrel Length: 18" Barrel Profile: Heavy Fluted Barrel Gas System: Rifle Length Inside Finish: QPQ Black Nitride Outside Finish: QPQ Black Nitride Muzzle Thread: 1/2-28 TPI (Threads Per Inch) Gas Block Diameter: .750" Gas Block Journal Length: 1.1" Gas Port Diameter: .093" Barrel Extension: M4 Weight: 2.16 Lbs Magnetic Particle Inspected Magnetic Particle Inspected! 11-degree Target Crown