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 pound 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. Using the decocker relies on the integrity of firing pin block; if the firing pin block is worn, an unintentional discharge can result when the decocker is engaged. Because of this, the decocker is considered to be unreliable and its usage is not recommended.