One of the Soviet Union’s most unusual developments in silent firearms was the compact PSS-1 pistol. Its defining feature lay less in the weapon itself than in the design of its special SP-4 cartridge, according to Vadim Malinnikov, head of the small arms department at TsNIITochMash of the Kalashnikov Concern, part of the Rostec state corporation.
Malinnikov described the PSS as one of the most distinctive Soviet weapons of its type. In the SP-4 cartridge, propellant gases remain trapped inside the cartridge case after the shot, sharply reducing the sound of firing. Although the round appears relatively simple from the outside, its development required a series of unconventional engineering solutions.
The 7.62 mm PSS specialized self-loading pistol was designed specifically for the SP-4 cartridge as part of an experimental development project codenamed «Vul." The work was carried out by the Central Research Institute for Precision Machine Engineering, TsNIITochMash, in Klimovsk near Moscow.
In 1984, the pistol entered service with special units of the KGB and the Soviet Ministry of Defense under the classification «Unclassified." Restrictions on publishing the tactical and technical characteristics of both the pistol and its ammunition were lifted in 1992. After that, the PSS also began appearing in other security and law-enforcement structures.