Igor Yakovlevich Stechkin, recently graduated in 1948 from the Tula Mechanical Institute, began work on this new automatic weapon concept, competing against other prolific designers such as Vojvodin and Kalashnikov. Stechkin designed a select-fire pistol capable of accurate fire up to 200 meters, with the possibility of attaching a combination holster/shoulder stock. Field-testing of the first prototypes was undertaken from April to June 1949. A 20,000 round endurance test against an Astra machine pistol and a PPS-43 submachine gun proved that Stechkin's design was promising. However, the testing board showed flaws of the prototype, such as the lack of adjustability of the rear sight, the high weight (1.9 kg with holster), short sight radius, and the recoil spring located under the barrel.