Our Old Testament Firearms HB-Series barrels produced in partnership with Hughes Ballistics are chambered in 5.56 NATO. This 7.5-Inch USGI Profile PISTOL-length Barrel is machined from 4150 Chrome Moly Vanadium steel with a Black Nitride QPQ Corrosion Resistant Finish and Black Nitride QPQ Corrosion Resistant coated M4 feed ramp extension.
4150 has a 0.50% carbon content and is used for barrels that need to be tougher, have more strength, and higher hardness than 4140 or 4130 can provide. It's a little less common and takes a little extra effort to machine but produces the right results.
Additional Info
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.
Old Testament Firearms
Old Testament Firearms
Ballistic Advantage
