At the beginning of the Great Patriotic War cccr required firearms which by its characteristics superior to all the world analogi.Zimoy 1942 Korovin, Rukavishnikov, Sudan, Shpagin, Degtyarev and others have begun to development of new, and at the time of the modern submachine gun with reduced dimensions compared with the PCA-41. From late February to mid-March had the first test samples of the shooting. After intensive work on upgrading and correcting deficiencies identified at the beginning of May 1942 was the second test result, the government has decided to launch a series of sub-machine gun Shpagina. The State Commission conducts tests paid special attention to reliability and resiliency of the new weapons and low cost of manufacture.

The disadvantages of this model submachine gun is the low accuracy of the battle by firing short bursts, especially it was noticeable when shooting without using the butt or what else upora.Nablyudalis frequent failures during solidification of lubricant in the cold season goda.Chustvitelnnost mechanisms submachine gun in contact with them and sand dirt, the difficulty of firing from armored vehicles, due to the presence of a powerful compensator at the muzzle of the barrel, a large mass of the system, especially with portable ammo that does not satisfy tactical and technical requirements. Removable wooden butt, on the one hand improved the pace and shooting accuracy, on the other inferior metal in the reliability of ekpluatatsionym and major mass-dimensional characteristics of the machine gun pistol folding metal stock. After contact with submachine gun water timber butt swell, which leads to greater efforts to separate and Attachments butt. When desiccation is a tremendous gap between gun machine gun and rifle. But all these shortcomings have not prevented the pca to become a legendary pistol gun in military history, not only the Soviet Union but the entire world’s history of weapons.