Devices and methods of converting semi-automatic firearms to a double-fire mode where a firearm fires a shot upon a single pull of a trigger, and fires a second shot upon a release of the trigger. A clip attachment can be constructed from a single component shaped to fit and mount onto the trigger and extend to protrude between and separate the foot of the safety-sear from the top of the trigger plate affecting the distance between the hammer engaging notch of the safety-sear and the hammer engaging notch of the trigger-sear which allows the firearm to discharge upon release of the trigger. Another version has a spacer pre-built onto a bottom portion of the pivotal safety sear.