22 ARC barrel caliber; The 1/7 twist rate is perfect for stabilizing heavy 22 ARC bullets, and the 5R rifling ensures excellent accuracy and consistency; 1/2x28 TPI muzzle thread; Barrel extension: M4, Nickel Teflon coated; Magnetic Particle Inspected; Recessed Target Crown; Crafted from high-quality 416-R stainless steel and stress relieved for maximum durability; Uses 6.5 Grendel bolt/BCG; The perfect choice for long-range shooting, hunting, or competitive shooting; With a rifle-length gas system and a 22" length, this barrel is perfect for long-range shooting; The extension is coated in a Nickel Teflon coating that maintains incredible dry lubricity, corrosion resistance; *Faxon Firearms recommends the use of an adjustable gas block with this barrel