The PDX™ U.R.G. is also equipped with newly invented Maxim HATEBRAKE™ Muzzle Booster. This patent-pending device significantly reduces recoil, decreases the flash signature, pushes gasses and concussion waves downrange away from the operator improving overall execution in short barrel pistols and rifles. The PDX U.R.G. uses a Direct Impingement system. ***Note*** This upper has a mil-spec BCG, so will not work with the SCW stock or PDW brace as is. SPECIFICATIONS WEIGHT: 4 lbsOVERALL LENGTH: 14 inchesBARREL LENGTH: 5.5 inchesCALIBER: 5.56MUZZLE THREADS: 5/8-24FINISH: Arid Earth Type-III Hard Anodizing FEATURES • HATEBRAKE installed under handguard• M-slot compatible handguard• Military grade materials [6Al-4V Titanium, 17-4 Stainless Steel, 7075 and 6061 Aluminum]• HK height rail for a more rigid upper receiver• Maxim Mil-Spec BCG FUNCTIONS • Optimized Personal Defense Weapon Upper• Increased reliability due to included HATEBRAKE• Optimized low flash and sound signatures• Designed to work with any Mil-Spec lower receiver