CZ 52 - Operation

Operation

The CZ 52's operating controls consist of a single-action trigger, an external hammer, a magazine catch located at the heel of the grip frame, and a combination de-cock/safety lever located on the left rear side of the receiver aft of the left grip panel. The manual safety blocks movement of the sear, which prevents the hammer from releasing and firing a round. A second safety, in the form of a spring-loaded firing pin block, prevents the pistol from firing unless the trigger is pulled fully to the rear; this feature renders the pistol "drop safe". However, if the firing pin block spring has become worn, the pistol may be rendered unsafe in the event of a muzzle down drop, or in the case of other internals being worn, it may be drop safe only when "cocked and locked", for instance. Care should be taken when handling firearms of uncertain origin, and only a competent gunsmith should be relied upon to verify the safety mechanisms of surplus guns are intact. Because the sear must overcome the additional spring pressure of the firing pin block, an inherent feature of the CZ 52 is its unusually heavy trigger pull, often in the 8-10 pounds range. The hammer is of the rebounding type, meaning that it does not contact the firing pin while in its uncocked position, and cannot do so unless the trigger is pulled, another safety feature.

Operation: After a full magazine is inserted, the slide is fully retracted, then released. This action cocks the hammer, strips a cartridge from the magazine, and chambers it. Rotating the 3-position safety lever fully downward, exposing a red warning dot between the receiver and the hammer pivot pin, renders the pistol ready to fire. Rotating the lever upward to its center position covers the red dot and engages the sear block (allowing "cocked and locked" carry). Finally, rotating the safety lever fully upward decocks the hammer by releasing the sear and intercepting the hammer's forward movement. This position allows safe carry of the pistol with a round in the chamber. The hammer must then be cocked manually and the safety disengaged before a round can be fired. As the trigger is pulled in this state, the trigger bar rotates the sear, a lug on the sear disengages the firing pin safety located directly above it, and the opposite side of the sear releases the hammer. The hammer then impacts the firing pin, the firing pin impacts the primer of the cartridge, and the shot is fired.

The CZ 52 utilizes a fairly uncommon short recoil operating system in which two vertical rollers are used to lock the barrel and slide together, via a cam block. This is similar to the system used in the German MG 42 machine gun, which itself hearkens back to a Polish patent of the 1930s. This arrangement results in an unusually strong lockup which, conventional wisdom holds, allowed the Czechs to load ammunition for it to higher pressure levels (and therefore, higher velocity and energy) than compatible ammunition manufactured in other Warsaw Pact countries. This oft recited "fact" is, however, debatable. The bottom of the CZ 52 chamber measures 0.058", whereas the supposedly weaker TT33 Tokarev pistol measures 0.125" at the bottom of the chamber.

While in battery (meaning the hammer is cocked, a round is chambered, and the pistol is ready to fire), the recoil spring, positioned coaxially around the barrel, provides the pressure necessary to lock the barrel and slide together via the rollers. When a shot is fired, the barrel and slide recoil together while the cam block is held stationary by a lug in the receiver. After traveling rearward a short distance (about 0.16" or 4 mm), the rollers are allowed to disengage from the slide via recesses in the cam block. At this point, the slide is free to continue rearward, cocking the hammer, extracting the spent case from the barrel's chamber and ejecting it clear of the pistol. After reaching the end of its stroke, the slide is returned to battery by the compressed recoil spring, again collecting a fresh cartridge from the magazine and inserting it into the chamber along the way.

When the magazine is empty, its follower presses against a catch, holding the slide open. The magazine catch is located at the heel of the pistol grip. It is pulled toward the backstrap, releasing the magazine from its well. A potential problem arises in that there is now minimal pressure on the magazine spring and the magazine catch is also under constant pressure from the mainspring, forcing it into contact with the rear of the magazine. This means that magazines do not drop free and occasionally take a few seconds to remove from the pistol. Releasing the slide catch is done by removing the empty magazine (or inserting a loaded one), then retracting the slide and releasing it. There is no thumb-operated lever to release the slide (though an aftermarket slide release lever is available).