Geissele CHF 5.56mm Barrel 12.5 in Chrome Lined. 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 CHF AR-15 5.56mm Threaded Barrel: Manufacturer: Geissele Color: Chrome Fabric/Material: Chromolly Steel Caliber: 5.56mm Barrel Profile: Tapered Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Twist Rate: 1-7 Barrel Material: Chrome Moly Vanadium Gun Make: AR Platform Gun Model: AR-15 Package Contents: Geissele CHF AR-15 5.56mm Threaded Barrel What firearm models does the manufacturer say Geissele CHF AR-15 5.56mm Threaded Barrel is compatible with? The manufacturer suggests that Geissele CHF AR-15 5.56mm Threaded Barrel is compatible with AR-15Geissele 05-2988: CHF 5.56mm Barrel 12.5 in Chrome Lined