A firearm includes a barrel portion, a slide, and a frame. The frame includes a grip, and the grip includes a magazine chamber and a rear surface adjacent the slide. At least one sensor is carried by the grip, and the at least one sensor adapted to sense a state of the magazine detachably received in the magazine chamber corresponding to a number of cartridges of ammunition remaining in the magazine. A display is carried on the rear surface of the grip, and the display includes a plurality of illuminating devices. The display is operatively coupled to the at least one sensor and is operable to visually present the number of cartridges of ammunition remaining in the magazine by illuminating at least one of the plurality of illuminating devices.