The Soviet Union adopted its first submachine gun in 1935 after trials of some 14 different design in 1932/33. The winner of the trials was Vasily Degtyarev, once of the Soviet Union’s most prolific firearms designers. His model 1934 was a simple blowback gun reminiscent of the MP-28,II albeit with different trigger and magazine systems. The PPD34 und a 25-round box magazine, chambered for 7.62x25mm Tokarev. It was put into slow production, with just 3,300 or so produced by the end of 1938. During that time, Degtyarev made a number of small improvements to the gun, smoothing out the teething problems that are always found in new production systems. This improved version was designated the PPD34-38.
During the time, the submachine gun was not considered a priority by the Red Army. The leading generals did not see the value in the class of arms, and actually pulled all the PPDs from service in 1939 and had them put into storage. Only a few months later, the Red Army would be given a grim demonstration of SMG effectiveness when they closed the border into Finland and encountered determined Finnish resistance with kp/31 Suomi SMGs.
Some Suomis were captured by Soviet troops, and were very well liked – for obvious reasons. The inevitable inquiry into why the Red Army did not have such a weapon led to a frantic re-issuing of PPDs and production of as many as possible. At Stalin’s direction, the Suomi drum magazine was copied and adapted to the PPD34-38 as well. This required the addition of a short feed tower to fit the magazine well initially deigned for a standard box magazine. While PPD34-38 production continued, the PPD40 was quickly designed and put into production alongside the older model. Eventually, both were replaced in service by the PPSh-41, which was truly deigned for mass industrial production.