History: The Vz.52 is a Czechoslovakian semi-automatic rifle developed in the late 1940s and fielded by that nation during the 1950s. It is a very similar rifle to the Soviet Union's Simonov SKS, in that not only are they comparable in form and function, but also in that both ultimately served only as short-lived stopgaps until assault rifles became available. It nonetheless remains in service with several nations and non-state groups, and still makes regular appearances in combat zones around the world.
The vz. 52 is a shoulder-fired semi-automatic rifle with 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. However, unlike most vertically-locking breech mechanism, the rifle's bolt has the unusual feature of tipping the bolt frontally to lock the mechanism, whereas other tipping bolt designs tip the bolt to the rear. The piston is actuated by residual gases from the bore, vented into a sleeve surrounding the barrel to overcome the inertia of the bolt carrier, bolt and the resistance of the return spring in order to unlock the chamber, eject the empty cartridge casing and then introduce a new round into the chamber upon return to battery.