Abstract: A circuit board that is added to a slide of an semiautomatic handgun for the purpose of counting fired rounds and providing a low ammunition round count signal, as well as a slide lock warning signal, indicating an out of ammunition condition. The circuit board is preferably saddle shaped with downwardly depending wings where warning lights can be located. The board is positioned between front and rear gun sights, below the aiming line of sight, with the saddle shape allowing placement of LEDs that can be seen behind the rear gun sight. In one embodiment, circuitry on the circuit board faces the slide so that the normal underside of the circuit board faces upwardly but below portions of gun sights that establish aiming.

Abstract: A gun sight system including a housing, comprised of a top housing layer and a bottom housing layer. The housing includes a front end and a rear end configured to adhere to the front and rear of the top surface of a gun slide. A central portion of the housing is configured to be perpendicular to the front top and rear top sections. Within the housing is a front and rear circuit board, including at least one battery mount, at least one switch, and a front LED and a rear LED. The housing has a window to allow light from the LED to shine into a window on a front and rear gun sight. A light pipe within each gun sight allows the light to be seen by the gun's user.

Abstract: A gun sight system including a housing, comprised of a top housing layer and a bottom housing layer. The housing includes a front end and a rear end configured to adhere to the front and rear of the top surface of a gun slide. A central portion of the housing is configured to be perpendicular to the front top and rear top sections. Within the housing is a front and rear circuit board, including at least one battery mount, at least one switch, and a front LED and a rear LED. The housing has a window to allow light from the LED to shine into a window on a front and rear gun sight. A light pipe within each gun sight allows the light to be seen by the gun's user.

Abstract: 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.

Abstract: 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.