The Heckler & Koch UMP (Universale Maschinenpistole, German for "Universal Machine Pistol") is a submachine gun developed and manufactured by Heckler & Koch. Heckler & Koch developed the UMP as a lighter and cheaper successor to the MP5, though both remain in production. The UMP has been adopted for use by various countries including Brazil, Canada, and the United States. A small number of UMPs chambered in .45 ACP were officially purchased by the 5th Special Forces Group of the United States Army Special Forces, with some of the weapons seeing limited service in the early years of the Iraqi insurgency, making them among the small number of submachine guns deployed by the U.S. military in recent conflicts. History The UMP was designed in the 1990s by Heckler & Koch (H&K), as a cheaper, lighter alternative to the MP5, which made heavy use of polymers. The UMP first entered production in 2000. It was designed primarily for use by American military and law enforcement units, as the MP5 was not available in .45 ACP, a round which was popular in the United States, but not in Europe. Despite the UMP's improvements and reduced cost, it did not replace the MP5, which ended up outselling the UMP. Design details The UMP is a blowback-operated, magazine-fed submachine gun firing from a closed bolt. The closed bolt increases the weapon's accuracy, which is particularly desirable in a law enforcement context. However, the simple blowback design of the UMP makes it less controllable than the MP5. As originally designed, the UMP is chambered for larger cartridges (.45 ACP and .40 S&W) than other submachine guns, to provide more stopping power against unarmoured targets, with slightly lower effectiveness at longer ranges. A larger cartridge produces more recoil, and makes it harder to control in fully automatic firing. To mitigate excessive recoil, Heckler & Koch designed the UMP to have a cyclic rate of fire of around 600 (±100) rounds per minute, though the rate of fire increases if (+ P) ammunition is used. The UMP9 (the 9×19mm version of the UMP) is almost lighter than the MP5. Its predominantly polymer construction reduces both its weight and the number of parts susceptible to corrosion. The UMP is available in four trigger group configurations, featuring different combinations of semi-automatic, 2-round burst, fully automatic, and safe settings. It features a side-folding buttstock to reduce its length during transport.