Slide block mechanism for semi-automatic pistols

A slide block mechanism for a semi-automatic pistol that locks the slide in battery and prevents the slide from reciprocating when the pistol is discharged. The slide block mechanism consists of a pair of aligned notches formed in the bottom edge of the slide and the top of the frame, and a pivoting slide block lever mounted to the frame that selectively seats within either of the aligned notches. The slide block lever can be manually switched to engage and disengage the slide block mechanism and is independent of the fire control and slide stop assemblies. The slide block lever has a protrusion that seats within the slide notch when engaged to prevent the slide from moving rearward and seats within the frame notch when disengaged for allowing normal operation of the slide.