The HK USP in .45 ACP is the largest of the standard USP variants, developed specifically for the US market and as a platform for the Mk 23 SOCOM program. The longer slide and barrel accommodate the .45 ACP cartridge. It was submitted and evaluated during the USSOCOM trials that resulted in the Mk 23 being selected. Type: Pistol Action: Semi-Automatic Caliber: .45 ACP Capacity: 12 Year introduced: 1995, Germany Weight: 30 oz Overall length: 7.87" Status: Active Military use: Yes Intended use: Military, Law Enforcement, Civilian Defense