At the end of Estonia's war of independence in 1920, the new nation's government began working on military infrastructure. One thing it would need was a repair depot to maintain military equipment, everything from barracks furniture to arms and vehicles. A large building was obtained in Tallinn (the capital city) and a number of small shop moved to the new premises to work together. Over the 1920s, this central repair depot grew in size and capability, and in 1924 is was officially named Arsenal Tallinn. It is probably best known for the design and construction of a series of Estonian armored cars, but in 1926 it took up a project to design and build a submachine gun. Building on experience making replacement parts for other weapons, Johannes Teiman (head of the Arsenal technical department) put together a design based largely on the German MP18.I.

The Tallinn SMG - which never had any more specific designation that I have been able to find - was simple blowback, used a progressive trigger fir semi and full auto firing, and was chambered for the 9x20mm Browning semi-rimmed cartridge. It fed from 50-round magazines that mounted at a slight backward angle to prevent rimlock. the design underwent a successful endurance test in November 1926, and slow mass production began. In total, about 630 appear to have been made (but that number is uncertain due to the 1940 destruction of Arsenal records). Most (437) went to the Estonian Defense League, with the remainder split between the Army and police.

The 9x20SR chambering was chosen because at that time, the official service sidearm of the Estonian Defense Forces was the FN 1903 pistol, chambered for the same 9x20SR. In the 1930s these were replaced by FN High Powers in 9mm, and Arsenal developed a modification to convert the SMGs to 9x19. This modification was ready in 1938, but never put into production. Instead, the existing SMGs were sold (a few to Latvia but most to Spain) and the money used to purchase brand new Suomi KP31 submachine guns from Finland. It appears that 485 Suomi's made it to Estonia before the Winter War. The Tallinn guns sent to Spain had a very low survival rate, and complete examples are extremely rare today.

Many thanks to the Estonian War Museum for allowing me to take this one out of their display to film for you. If you find yourself in Tallinn, definitely take time to stop by and check them out! Hours and rotating exhibits are available on their web site: https://esm.ee