The .223 Wylde chambered barrels are machined from 416 Stainless Steel with a bead blasted finish. Our Premium Series Barrels feature a Nickel Boron Coated Extended M4 Feed Ramp Extension. Hanson Series Barrels feature Ballistic Advantage's proprietary BA Hanson profile. Hanson barrels are not designed to work with aftermarket piston kits. All NFA/ATF Rules Apply You may use this barrel with a lower receiver that is a Registered SBR, Machine Gun, or Pistol. Possession of this barrel along with a Non-NFA lower receiver is Prohibited, except when installed on a Pistol configuration firearm. Additional Info Material: 416R Stainless Steel Finish: Bead Blasted Mfg: Ballistic Advantage