Geissele CHF 300 Blackout Barrel 8 in Taper Chrome Lined1/2x28 1-7 Twist Mid Length Tapered. Our barrels are High Pressure Tested (HPT) and Magnetic Particle Inspected (MPI). The accuracy and reliability of Geissele CHF barrels makes them an ideal choice for a hard use duty weapon precision tuned competition gun and everything in between. Specifications for Geissele Chrome Lined 300 Blackout Threaded AR Barrel: Manufacturer: Geissele Caliber: .300 AAC Blackout Barrel Length: 8 in Barrel Profile: Tapered Gas System Length: Mid Length Barrel Twist Rate: 1-7 Firearms Threads Per Inch: 1/2x28 Package Contents: Geissele Chrome Lined 300 Blackout Threaded AR Barrel Geissele 05-3428: CHF 300 Blackout Barrel 8 in Taper Chrome Lined1/2x28 1-7 Twist Mid Length Tapered