A system for displaying a number of rounds in a magazine of a weapon may include a force sensitive resistor shaped to be placed in the magazine and engage a magazine spring therein such that a resistance of the force sensitive resistor changes in response to a spring force from a number of rounds in the magazine, a microcontroller connected to detect the resistance of the force sensitive resistor resulting from the spring force upon the force sensitive resistor in response to the number of rounds in the magazine and output an electrical signal indicative of the resistance; and a display connected to respond to the electrical signal, the display having an indicator that is actuated in response to the signal to indicate the number of rounds in the magazine.