A lack of experience of Strąpoć in machine guns' designing and lack of direct patterns resulted in several original construction features, similar to semi-automatic pistols, and hence the weapon is sometimes referred to as a machine pistol, in spite of a size and general layout closer to a submachine gun. The weapon had no stock and had quite compact dimensions. It used standard German 9mm Parabellum ammunition which could be easily obtained either by purchase from the German soldiers or through armed actions. Three or four last weapons used 7.62×25mm Soviet ammunition, of growing popularity among partisans.