The M1951 is a short recoil–operated, locked breech pistol with a vertically falling locking piece and an open top slide (the locking mechanism design was influenced by the Walther P38 pistol). The locking piece, located under the barrel, is unlocked by a sliding pin and locked back into battery by a beveled surface on the pistol's frame. The locking piece features two locking lugs that engage appropriate recesses cut into the slide's internal side surfaces. When the pistol is fired, the locking piece, integral with the slide, goes back together with the barrel which is locked to the slide. After a brief period of unrestricted travel of approx. the unlocking pin on the rear barrel lug strikes the receiver and stops. As the barrel and slide continue back, the locking piece strikes the stationary plunger and is forced down into recesses in the slide. The barrel comes to rest but the slide continues rearward for a further . Upon forward return, the slide picks up the barrel and the locking piece on the barrel lug is lifted up by the receiver cam to lock the barrel to the slide. The spring-loaded extractor is integrated into the slide, and the fixed-type ejector is integral to the pistol's frame. The pistol has a hammer striking mechanism (with an exposed hammer) and a single-action trigger with a disconnector, which enables semi-automatic fire only. A cross-bolt safety mounted on the weapon's frame (beneath the hammer) provides safe operation with a cartridge introduced into the chamber. In the “weapon safe” position (the safety's button pushed in to the left) the slide catch is disabled.