In the mid-1920s, the Army of Estonia took delivery of a new submachine gun - a homegrown product known as the "Tallinn Model 1923" (or the "Arsenal M23"). The gun emerged from the Estonian military arsenal at Karjamaa, Tallinn and thus received its name from its place of origination. This little-remembered weapon appeared in the post-World War 1 era and fewer than 600 were completed (sources state approximately 570 units being made). The series saw service with military and police forces within Estonia and found renewed life during the Spanish Civil War (1936-1939) where it fought under the banner of the Spanish Republic.
Design work, attributed to Johannes Teiman, began in 1926 and resulted in a submachine gun borrowing much of the form and function of the German Bergmann MP18/1 - a development of the German Empire encountered during the latter stages of World War 1 and becoming the first practical submachine gun anywhere in the world.
The Estonian take on this gun involved chambering for the 9x20mm SR Browning cartridge to keep it in line with the Army's FN M1903 semi-automatic service pistol (as it used the same ammunition). Overall length was 809mm with a barrel measuring 210mm long. The internal action was blowback and feeding was by way of a 40-round detachable box magazine. Rate-of-fire was 600 rounds-per-minute with a muzzle velocity of 365 meters-per-second. Iron sights allowed for ranging out to 600 meters.
Like the Bergmann design, the Model 1923 used a single wood piece to form the forend, receiver base, grip handle, and shoulder stock. A perforated jacket (horizontal slots) was set around the barrel to accentuate air-cooling and, in addition to this, cooling fins were machined directly onto the barrel. Unlike the Bergmann, a revised bolt was fitted that featured a smaller frontal aspect. Sling loops were added under the barrel jacket and under the shoulder stock. The trigger unit was underslung in the typical fashion for a submachine gun of the period.
The Tallinn Model 1923 entered service in 1926 and was in constant use up until about 1940, some eventually being sold off to Latvia. It was given up by Estonia sometime in the early 1930s however and never made a comeback as the Army moved on to the long-lasting Suomi KP/-31 submachine gun originating from Finland. The Model 1923 then fell to firearms history - one of the few guns to have ever come out of Estonia.