A semi-automatic firearm includes a frame and a movable slide mounted on the frame. The slide defines an ejection port and lateral walls that extend longitudinally from a rear face of the slide to adjacent a front face through which an opening is formed to permit egress of a round of ammunition, the rear face and the front face being generally perpendicular to the lateral walls. The firearm further includes a firing mechanism and an access port formed in the lateral walls of the slide.