Kulsprutepistol m/45 (Kpist m/45) also known as the Carl Gustav M/45 or the Swedish K SMG, is a 9 mm Swedish sub machine gun adopted in 1945 (hence the designation m/45) at the Carl Gustaf G-F facility in the city of Eskilstuna by Swedish weapons designer Gunnar Johnsson. The m/45 was the official sub machine gun of the Swedish Army after World War II. The m/45 was also used by U.S Special Forces in the Vietnam War, these weapons were devoid of markings. In U.S service it was known as \"K-Rifle\" or \"Swedish-K\".The m/45 was developed in 1944-45 lending and improving many design elements from earlier sub machine guns. The sheet metal stampings used in manufacturing the German MP40, the British Sten, the Soviet PPSh-41 and PPS-43 were studied in detail. A prototype version was ready for testing in 1944 and the first production version was adopted in 1945.An interesting difference between the m/45 and most modern self loading pistols and rifles is that it is carried with the bolt in a retracted position and an empty chamber. When the trigger is pulled, the bolt charges forward, pulls a cartridge from the magazine, chambers and fires it. This results in a lock time so long that the shooter actually notices the split second between the release of the sear and the discharge of the bullet.