The HK UMP is a German submachine gun chambered in larger cartridges such as the .45 ACP and .40 S&W. Developed in the 1990s by Heckler & Koch, it was developed as a lighter and cheaper option to the MP5, despite both remaining in production. The HK UMP has been used by several agencies and military forces including the U.S Customs and Border Protection.
Blowback-operated, magazine fed submachine gun, the HK UMP uses larger cartridges to give more stopping power against unarmored targets. It can be interchangeable between 3 calibers: the UMP45 (.45 ACP), the UMP40 (.40 S&W), and the UMP9 (9x19mm Parabellum). All versions have the same design and can be cross-converted with one another by replacing the bolt, barrel, and magazine.