The HK USP (Universal Self-loading Pistol) was HK's response to the US military modular handgun requirement of the late 1980s. The 4.25-inch barrel and polymer frame represented HK's first polymer service pistol. The USP's recoil-reduction system — a buffer in the recoil spring assembly — was designed for .45 ACP but carried over to all calibers. The USP established the ergonomic and mechanical template that all subsequent HK pistols follow. Type: Pistol Action: Semi-Automatic Caliber: 9mm Capacity: 15 Year introduced: 1993, Germany Weight: 26.47 oz Overall length: 7.64" Status: Active Intended use: law_enforcement, service, military