A device for indicating a limited amount of remaining ammunition in a firearm magazine is disclosed. A switch is mounted within the magazine, to a plate at a bottom end of the magazine. The plate may be a magazine insert, a floor plate, a base plate or a base pad. The switch cooperates with or responds to a segment or portion of a magazine spring. An indicating terminal is coupled with the switch. A change in state of the switch activates and deactivates the indicating terminal. The indicating terminal may be electrically connected to an indicating device. The indicating device may be an LED, an incandescent bulb or a light. The “on” and “off” states of the switch correspond to differing positions of the segment of the spring relative to the switch or to the plate and attendant differing amounts of ammunition in the magazine.