The UMP9 is the 9mm variant of the Universal Machine Pistol, HK's polymer-framed successor to the MP5. The UMP features a simple blowback operation rather than roller-delayed, reducing manufacturing complexity and cost. It includes a side-folding stock and Picatinny rail system. Adopted by US Customs and Border Protection and numerous other agencies. Type: Submachine Gun Action: Semi/Full-Auto Caliber: 9mm Capacity: 30 Year introduced: 1999, Germany Weight: 73.6 oz Overall length: 17.7" Status: Active Intended use: law_enforcement, military