Franklin Armory BFSIII CZ Scorpion (Binary Trigger)

The Franklin Armory BFSIII CZ Scorpion is a binary firing system that fires one round when the trigger is pulled and a second round when the trigger is released. It is ATF-classified as a semi-automatic trigger, not a machine gun, and is legal in most states (some states restrict binary triggers; check your jurisdiction). The selector has three positions: safe, standard semi-auto, and binary. In binary mode the shooter can pull the trigger to fire one round, then move the selector to safe before releasing to abort the release shot.

The kit ships with the same internals across both shoe options. The CZ-C1 has a curved trigger shoe matching the factory feel, and the CZ-S1 has a flat-faced straight shoe that some shooters find easier to maintain consistent finger placement on under doubled rate of fire. Both ship with an ambidextrous safety selector, so the BFSIII install also covers the factory safety upgrade.

Compatibility is straightforward on the original EVO 3 family (S1, S2, pistol, carbine) where Franklin Armory has fully tested the trigger. On the new Scorpion 3+ Micro, user reports confirm functional fitment but Franklin Armory has not yet certified the install in their official documentation, so going this route on a 3+ is mildly off-warranty until they update their compatibility statement. The BFSIII is the most expensive Scorpion trigger upgrade but adds a capability no other trigger in the catalog provides.