Faxon Firearms Duty Series Features The Faxon Firearms Duty Series barrel uses a chrome-lined bore that resists corrosion fouling and erosion under sustained firing extending service life compared to an unlined bore. Built from 4150 CMV steel it meets mil-spec material standards chosen specifically for strength and longevity in hard-use environments. The medium taper profile balances heat resistance with a lighter more maneuverable feel than a heavier government profile barrel making it well suited to duty and defensive use. A carbine-length gas system rounds out the design for proven reliability across a wide range of platforms and ammunition types. Every Duty Series barrel undergoes MPI inspection air-gauge testing and headspace verification before it leaves the factory giving shooters confidence in both the metallurgy and the precision of the finished part. The black chrome mag phosphate exterior finish protects the barrel from wear moisture and general environmental stress over years of use. At 12.5 inches with a 1/2x28 thread pattern this barrel is ready to accept a muzzle device or suppressor without additional gunsmithing. For shooters building or upgrading a duty-oriented AR-15 this Faxon barrel offers a combat-tested combination of durability and precision. Faxon Firearms Duty Series Specifications Brand: Faxon Firearms Model: Duty Series Caliber: 5.56 NATO Length: 12.50 Color: Black Material: Chrome Moly Vanadium Finish: Chrome Mag Phosphate Barrel Type: Button Rifled Twist Rate: 1:7 Diameter: .750 Thread Pattern: 1/2x28 Weight: 1.49 lbs Gas System Length: Carbine Length Available At: GrabAGun