Producted in numbers, totalling more than 6 million in all, the PPS-41 was one of the primary weapons, submachine gun or otherwise, of the Soviet troops during WWII. The PPS-41 is a blowback-operated selective-fire automatic submachine gun. Both accurate and having a relatively long range, when compared with other submachine guns. The PPS-41 was developed by George Spagin and, as a result, the PPS-41 is also often referred to as the Spagin. In the end of the PPS-41 was so popular that the design was exported to numerous countries like Hungary, as well as was copied by the Chinese.
Spagin (PPSh-41G) on Wikipedia