The vz.52/57 is a Czechoslovakian self-loading rifle converted from the vz.52 that had started development in the 1940s as a replacement for the vz.24 Mauser type rifle in service with the Czechoslovakian army. After WWII ended many nations realized the need for an intermediate cartridge that would better serve the changing ways of modern combat. Russia developed the 7.62x39mm M43 round during the war and accelerated its improvement after the war ended. Czechoslovakia was also working along the same lines at the same time and developed the 7.62x45mm M52 that they believed to be superior to the Russian cartridge.
The vz.52, full name 7.62mm Samonabíjecí Puška vzor 52 (vzor meaning ‘model’) was designed by brothers Jan and Jaroslav Kratochvíl in the early 1950s. It came into service in 1952 and was manufactured by Považské Strojárne Považská Bystrica and later by Česká Zbrojovka Uherský Brod (famously known as CZ). It continued service for five years in the caliber of 7.62x45mm until mid-1950s when the Soviet Union demanded Czechoslovakia conform to the ammunition standardization of the Warsaw Pact countries to 7.62x39mm.
Existing vz.52 rifles were then sold as surplus to allied communist countries or converted to the new caliber of 7.62x39mm. Exact numbers of the conversions are unknown and most vz.52/57s were manufactured new as it was easier and more cost effective and the existing vz.52s easily sold as surplus.
The vz.52/57 is identical to the vz.52 except for caliber, barrel, and magazines. The vz.52/57 has a tilting-bolt locking mechanism powered by an annular short-stroke gas piston system. The bolt is locked by two lugs that recess into slots machined into the receiver. The rifle’s bolt is different by tipping to the front to lock the mechanism where most other tipping bolt designs tip to the rear. The piston is actuated by residual gases from the bore that vent into a sleeve surrounding the barrel to overcome the inertia of the bolt carrier and bolt as well as the resistance of the return spring to unlock the chamber and eject the spent cartridge case. The ejection pattern is unusual as well ejecting to the left or forward left. The vz.52/57 trigger mechanism closely resembles the U.S. M1 Garand and the safety switch is inside the trigger guard as well. Similar to the SKS it has a folding bayonet but the vz.52/57 bayonet folds to the side into a recess in the stock.
The vz.52/57 unlike its predecessor featured a chromium plated bore and chamber. The magazine for the vz.52/57 was also redesigned changing the taper slightly. While the magazines for the vz.52 were interchangeable with the vz.52/57 they did not feed efficiently and caused issues with reliability for the rifle.
The Vz.52 and Vz.52/57 are very difficult to visually distinguish but there are a couple points that can tell them apart. The Vz.52 has a parkerized finish, a shallow slope on the underside of the magazine, and no barrel crosspin in the forward receiver. The metal on the Vz.52/57 is painted black, the slope of the underside of the magazine is noticeably steep, and a crosspin was added to the front of the receiver under the rear sight.
Despite converting to the 7.62x39mm as demanded by the Soviet Union the vz.52/57 would only stay in service for one year. It was replaced by the select fire vz.58 which was Czechoslovakia’s answer to the Russian AK-47.
Though it had a very short service life with Czechoslovakia the vz.52 and vz.52/57 would continue to be used in many other nations allied with the Eastern Bloc. Cuba under Fidel Castro purchased a very large quantity of both models and they would be used famously during the Bay of Pigs invasion of 1961. Many were then sent from Cuba to African conflicts in Angola as well as the 1960-65 Congo Crisis. The vz.52 and vz.52/57 have also turned up in the Vietnam War, the Ogaden War Somalia vs Ethiopia, the Soviet-Afghan War, the Somali Civil War and quite notably the U.S. invasion of Grenada in 1983. Captured cz.52s and 52/57s from Grenada came back to the United States with soldiers as either authorized legal ‘bring backs’ or by unapproved means.