This .300 Blackout chambered 8" Modern Series Barrel is machined from 4150 Chrome Moly Vanadium steel with a QPQ Corrosion Resistant finish and QPQ coated M4 feed ramp extension. Specs- 750" Gas block journal, gas system length- pistol and a DRP profile. All NFA/ATF Rules ApplyYou 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. Product Specifications Model: Modern Series Caliber: 300 Blackout Firearm Fit: AR-15 Length Range: 6"-10" Color: Black Material: Chrome Moly Vanadium Steel Sights: None Finish: QPQ Barrel Type: Pistol Length Twist: 1:7" Length: 8" Thread Pattern: 5 / 8"x24 Weight: 19 oz Barrel Features: DRP Profile