The HK USP (Universal Self-loading Pistol) Gas Blow-Back Pistol (GBB) is an authentic replica of the Heckler & Koch USP semi-automatic pistol. The USP was developed around the early 90Â’s as a replacement for the P7 series of handguns by H&K. H&K focused on the American market when designing the USP and it is highly influenced by elements found in popular US handguns such as the 1911. The USP has been accepted into many US law enforcement and military organizations and has gained popularity in international markets as well. The HK USP gas blowback airsoft pistol maintains the same reliability and focus on performance as its real life counterpart. It features authentic H&K trademarks, a moving hammer, a functioning de-cocker, a polymer lower frame with a metal slide, a universal mounting grove for weapon attachments, an oversized trigger guard for use with gloves, an ambidextrous magazine release lever, a textured pistol grip for improved weapon handling, and fixed white dotted iron sights for quick target acquisition. Features - Polymer frame with aluminum slide with officially licensed Heckler and Koch trademark - Ambidextrous trigger guard mounted magazine release - Textured grip provides superior grip regardless of the conditions - Enhanced slide release - Functioning safety / decocker - Drop free magazine - Realistic blowback action FPS Range: 340-350 Color: Black The USP is a semi-automatic pistol with a mechanically locked breech using the short recoil method of operation. This rather conventional lock-up system has a large rectangular lug over the barrels chamber that rides into and engages the ejection port cut-out in the slide. When a cartridge is fired, pressures generated by the ignited powder drive the cartridge casing back against the breech face on the slide, driving back both the barrel and slide as they remain locked together in the manner described above. After 3 mm (0.12 in) of unrestricted rearward travel, the projectile has left the barrel and gas pressures have dropped to a safe level. A shaped lug on the underside of the barrel chamber comes into contact with a hooked locking block at the end of the steel recoil spring guide rod, lowering the rear end of the barrel and stopping the barrel's rearward movement. The recoil spring assembly is held in place by the slide stop levers axis pin and a round cut-out at the front of the slide. For enhanced reliability in high-dust environments, the locking surface on the front top of the barrels locking lug is tapered with a forward slope. This tapered surface produces a camming action which assists in positive lock-up in the presence of heavy fouling and debris. Dimensions: 210mm x 150mm Magazine: 26+1 rounds. Compatible with KWA USP magazines Gas Type: Green Gas, Red Gas, Propane Firing Mode: Semi Automatic, Safety System: Gas Blowback Hopup: Yes, Adjustable Package Includes: Gun, Magazine, and Manual