in a submachine gun) with higher velocity and energy than compatible ammunition manufactured for pistols of a similar caliber in other Warsaw Pact countries. In practice, however, the rollers were generally poorly heat treated resulting in them deforming and grinding against the inside of the slide and frame; an issue that can cause both to crack if not addressed. The firing pin and extractor have similar problems with heat treatment; it is recommended to replace them with aftermarket parts. When cocked, loaded, and closed; the recoil spring, positioned coaxially around the barrel, provides the pressure necessary to lock the barrel and slide together via the rollers. When a round is discharged, 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 cocked and loaded by the compressed recoil spring, again collecting a fresh cartridge from the magazine and inserting it into the chamber. When the magazine is empty its follower presses against an externally mounted slide catch and holds the slide open. The slide catch can be manually engaged by pressing up on the exposed bar. The magazine catch is located at the heel of the pistol grip. It is pulled toward the backstrap to release the magazine from the well. A potential problem arises in that there is now minimal pressure on the magazine spring and the magazine catch is 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 (although an aftermarket slide release lever is available). Ammunition By the late 1990s, after the popularity of the surplus CZ 52 had started to increase, hollow-point ammunition in 7.62×25mm became available from custom shops. The pistol proved