Prior to the Winter War, Finland had just a few armored vehicles; mostly armored cars. These needed some armament, and one idea put forth was to fit an m/31 Suomi to a ball mount inside a vehicle. This required simply designing a specific shroud for the barrel to fit the mount (as well as the pistol grip frame like the Korsu/bunker model), and a spare standard shroud could be carried as well, so the Suomi could be taken out and used if the vehicle needed to be abandoned. Only a few dozen were originally made, and they were all out of service before the end of the Continuation War.
During the wars, Finland was able to capture some Soviet armor, and also a large number of Soviet DT guns. These couple perform the same role as the tank model Suomi, already fit the captured Soviet vehicles, and offered a more powerful cartridge. They completely replaced the small number of tank Suomis in service use.