Finnish Precision: Aimo Lahti's Famous M/31 Submachine Gun

By Michael Heidler

The “Suomi” is one of the best-known Finnish weapons of the Second World War. It stands for perfect quality and the highest precision. It also taught the Russian invaders the meaning of fear.

Its creator was Aimo Johannes Lahti. Born in the town of Viiala in 1896, he left school after only six years and got a job in the local glass factory. With his first earnings, he bought an old Russian Berdan rifle. The mechanism of the rifle awakened his interest and, together with a local gunsmith, he began to examine it and to tinker with other weapons in the workshop. After his military service in 1918/1919, he began to work as a gunsmith in the Keski-Suomi regiment in June 1921. At this time, the army was still using German Bergmann MP 18 submachine guns and Finnish copies of the M/20 made under license. Lahti did not like these guns—in his opinion, they were too heavy, unwieldy and too expensive to produce. Therefore, he began thinking about creating his own submachine gun, and in the following months he worked hard on a first draft.

The first prototype he ordered was a downscaled weapon in 7.65x17mm caliber (aka .32 ACP), only about 11.8 inches long and made by a blacksmith in Viiala. The result was no work of art, but it proved that the basic construction that Lahti had designed could work well. In 1922, he ordered the first full-size prototype “M/22,” which was made by the machine workshop Leskinen & Kari in Tampere in 7.65x21mm caliber. The gun had the same rate of fire as the later M/26.

In June 1924, Lahti established the company Konepistooliosakeyhtiö (or Submachine Gun Ltd.) with some officers of the same regiment. The other shareholders of this new business enterprise were Captain V. Korpela, Lieutenant Y. Koskinen and Lieutenant L. Boyer-Spoof. The new company had ambitious plans but very limited finances.

Lahti was working hard on his submachine gun design and making several improvements. Konepistooliosakeyhtiö ordered 100 submachine guns from Ab Tool Oy, and, in August 1924, the Finnish...

This article first appeared in Small Arms Review V22N1 (January 2018)
and was posted online on November 17, 2017


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