Griffin Armament 9.5 inch 300BLK HEDP Barrel w/Gas Block. Griffin Armament built these Rifle Barrels from 416R stainless steel for maximum hardness with a black nitride finish and these Griffin Armament HEDP Rifle Barrels are hand lapped to ensure each one is built to the highest quality possible. The Griffin Armament 300 BLK HEDP Barrel w/ PRIMO Gas Block features a medium diameter between the chamber and gas block to ensure low-bullets are shifted when firing with a suppressor. Plus there's a polished M4 feed ramp and gas ports to ensure smooth feeding chambering and extraction. These barrels are all paired with a 416R low profile PRIMO Gas Block which has a medium profile for reliable function with suppressors and is capable of handling both supersonic and subsonic ammunition. Install this Griffin Armament 300 BLK HEDP Barrel w/ PRIMO Gas Block to get one of the best barrels the shooting industry has to offer. Specifications for Griffin Armament Griffin 300BLK HEDP Barrel w/Gas Block: Manufacturer: Griffin Armament Finish: Black Nitride Caliber: .300 AAC Blackout Barrel Length: 9.5 in Barrel Profile: M4 Gas System Length: Pistol Length Barrel Twist Rate: 1-8 Condition: New Package Contents: Griffin Armament Griffin 300BLK HEDP Barrel w/Gas Block Griffin Armament HE95300B: 9.5 inch 300BLK HEDP Barrel w/Gas Block