The Franklin Armory Binary Firing System will allow you to put more rounds downrange with a pull and release of the trigger.
There it is: an entire AR-15 or modification to an existing AR-15 rifle that will allow you to simulate automatic fire. While on the range, you can put tons of fire downrange when the selector is set in binary fire mode. You also achieve a higher rate of fire by shooting a round while pulling the trigger, and another when releasing the trigger, which is about as close to full-auto as you can get with quick trigger manipulation.
While the system in this review did not work flawlessly, there was consistent fire on target after a bit of range time, which clearly makes it an entertaining AR-15 rifle shoot.
The Franklin Armory Binary Firing System is something that any AR-15 fan may well consider having for recreational shooting at your local gun club.