These 300 Blackout chambered Performance Series Barrels are machined from 4150 Chrome Moly Vanadium steel with a QPQ Corrosion Resistant Finish. Performance Series Barrels feature a Nickel Boron Coated Extended M4 Feed Ramp Extension. Hanson Series Barrels feature Ballistic Advantage's proprietary BA Hanson profile and include a pinned lo-pro gas block. 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. Mfg: Ballistic Advantage