The submachine-gun is a compact automatic weapon firing pistol ammunition, designed for short-range assault and close-quarter fighting and was first used by the German Army in 1917. The Thompson submachine-gun was not ready in time for the First World War but was used in the 1920s by American gangsters. They were also being employed by the United States Army and during the war the Savage Arms Corporation producing over 90,000 of these Tommyguns a month. Although heavier than other submachine-guns, it was considered the most reliable available.
In the early stages of the Second World War the British Army purchased the Thompson submachine-gun from the United States. These were expensive and in 1940 they switched to the Sten Gun made by the Royal Small Arms Factory in Enfield. Over the next five years the company supplied 4 million of these weapons to the army. It was not popular with the soldiers because its habit of jamming when being used in battle. However, they were cheap to buy and the British government distributed them to resistance groups throughout occupied Europe.
After 1934 the Red Army issued their soldiers with the Degtyarev PPD submachine-gun. It used a drum magazine holding 71 rounds of 7.62mm pistol ammunition. In 1940 it was replaced by a new model that improved the magazine and its method of attachment. Army officers liked the Degtyarev because it was simple to operate and its firepower encouraged their men to act aggressively against the German invaders.
In 1938 the German Army began issuing the MP38 submachine-gun to its soldiers. Two years later it was replaced by the cheaper and more efficient MP40.