Abstract: A firearm with a firing mechanism having a hammer, a trigger, a semi-automatic disconnector, an automatic sear, and an electro-mechanical movement mechanism for moving the automatic sear. The trigger and semi-automatic disconnector can be used to fire the firearm in a semi-automatic firing mode. The electro-mechanical movement mechanism can control release of the hammer by the automatic sear, but only after a first firing of the firearm by release of the hammer from a mechanical interlock with the trigger. The electro-mechanical movement mechanism has an actuator attached to a piezoelectric member. The piezoelectric member moves the actuator to move the automatic sear between a hammer holding position and a hammer release position.