This 9mm chambered straight profile barrel is machined from 4150 Chrome Moly Vanadium steel with a QPQ Corrosion Resistant Finish and 1/2-28 x .400 full profile threads. Available in 8.3", 11", and 16" lengths. Designed to work with both Colt/RR and Glock style AR builds Compatible with EPC upper receivers, as well as standard mil-spec upper receivers 9mm on an AR15 platform operates by blowback and does not need a gas block or gas tube Threaded 1/2x28 to give you versatility when choosing a muzzle device Integrated barrel extension Since the "barrel extension" is an integral part of the barrel, the length stated is the tru Mfg: Aero Precision