The Suomi KP/-31 () is a Finnish submachine gun that was mainly used during World War II. It is a descendant of the M-22 prototype and the KP/-26 production model, which was revealed to the public in 1925. It entered service in Finland in 1931, and remained in use until the 1980s.

The Suomi KP/-31 is regarded by many as one of the most successful submachine guns of World War II. It also had a profound effect on the conflict beyond Finland as the Soviet authorities, who had been dismissive of submachine guns, were persuaded of their fatal efficiency by the Finnish forces in the Winter War of 1939–1940. Though a relatively early design, the Suomi was a formidable weapon: highly controllable and with accuracy similar to that of the mass-produced PPSh-41 but at the cost of a significantly higher mass to absorb recoil, with a lower rate of fire and an equally large magazine capacity.

A specialized bunker version was also produced in very small numbers (a total of 500 built) in 1941, the barrel shroud end of which was thinner and flattened to allow firing through the narrow ports of defensive bunkers. This version had no shoulder stock and was equipped with a pistol grip. An even rarer version "900 kp 31 psv"

  • : Commercial KP/31 with bipod, around 8 were purchased for the Special Police in the Federal District. Each of its four "shock detachments" was armed with two Suomis, two Bergmann submachine guns and two Thompsons.
  • : 5,000 were bought from 1940 to 1942.
  • : 1,250 were bought from 1940 to 1942, of which 500 were delivered.
  • Republic of the Congo: Ex-Swedish Husqvarnas left over from the ONUC were used as late as the 1970s.
  • : 32 were bought from Finland, some Swedish m/37-39 were also purchased and 1,400 copies, designated m/41, were manufactured in the kingdom during WWII until Germany disarmed all the Danish army in August 1943.
  • : Used Swedish-made kpist m/37-39s.
  • : Five KP/-26 were purchased for evaluation. 485 KP-31 were delivered in September 1938.
  • : 150 KP/-31 seized from various sources were supplied to French troops during the Phoney War.
  • : Used Swedish-made kpist m/37-39s.
  • : Mix of military surplus and commercial contract guns acquired from unknown sources by Haganah.
  • Italian Partisans: Used examples captured from German soldiers
  • : 3,042 were ordered by Germany from Finland during WWII and likely issued to the Wehrmacht and SS. Also 120 Suomi KP's were presented to the German troops of AOK Norwegen in 1942 for use on the Finnish Front. Most of these weapons left Finland with German troops in 1944 and were subsequently used in other theaters of the war. Any Suomi KP's captured from Denmark designated as the Maschinenpistole 746(d)
  • : Swedish m/37-39 variant used by police troops in Sweden.
  • : Used by both sides during the Spanish Civil War
  • : 100 KP/-41 delivered (of 5,000 ordered) and designated MP 43. 22,500 produced under license by Hispano-Suiza as MP 43/44.
  • : Pontifical Swiss Guard used the Hispano-Suiza version until the 1970s.

<gallery heights="100" widths="180">

File:Suomi M31 Korsu.JPG|Bunker model KP/-31

File:Suomi.png|Internal drawing of the Suomi from the original patent

File:Vuosalmi etulinja 1944.jpg|A Finnish sub-machinegunner during the Battle of Vuosalmi in Karelian Isthmus

File:Suomi M26 Rajamuseo.JPG|Early 7.65&nbsp;mm Suomi KP/-26

</gallery>

See also

  • List of submachine guns

References

  • Guns of the Third Reich, p.&nbsp;163