This 5.56 chambered 10.5 inch Government Profile Modern Series Barrel
is machined from 4150 Chrome Moly Vanadium steel with a QPQ Corrosion
Resistant Finish and QPQ coated M4 feed ramp extension. 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.