A firearm for mechanically and electronically firing a weapon including a trigger rotatably mounted to a sear and having an actuator attached thereto. A secondary sear is rotatably mounted to the sear, and a switch is mounted to the lower receiver behind the trigger and adapted to be contacted by the actuator when the trigger is pulled. An electronic circuit is electrically connected to the switch such that when the switch is contacted the circuit is energized to operate a prime mover that operates the firearm. The sear assembly may also comprise a main sear and an auxiliary sear controlled by a selector switch having cam surfaces and adapted to be rotated to a plurality of positions, wherein in a first position comprises a safety mode, a second position comprises a mechanical mode of fire and a third position comprises an electronic mode of fire.