Glock Switch vs. Binary Trigger

You’re looking at your Glock and thinking about a faster rate of fire. The two main hardware options are a Glock auto-sear (a “switch”) or a binary trigger. One is a small, simple metal part that replaces your rear slide cover plate. The other is a complex, drop-in trigger assembly. The difference in function, legality, and performance is absolute.

How They Work: The Mechanical Reality

A Glock switch is a forced reset auto-sear. It’s a single, precision-machined component, typically made from hardened steel or aluminum. When installed in place of the rear slide cover plate, its sear arm intercepts the trigger bar’s rearward travel as the slide cycles. This forces the trigger to reset forward instantly, engaging the disconnector and firing the next round as long as you maintain rearward pressure. It’s a purely mechanical conversion that leverages the pistol’s existing blowback operation. In contrast, a binary trigger is a self-contained fire control group. It uses a specialized disconnector and trigger mechanism. Pulling the trigger fires a round on the pull, and releasing the trigger fires a second round. The reset is not forced by the slide; it’s a function of the trigger’s designed travel path. One modifies the factory system, the other replaces it entirely.

Rate of Fire: Practical vs. Theoretical

This is where the rubber meets the road. A properly installed switch on a Glock 17 or 19 can achieve rates exceeding 1,200 rounds per minute. It’s functionally full-auto. Control is difficult, and a standard 17-round magazine empties in under a second. A binary trigger’s rate is limited by your finger speed. The fastest you can pull and release determines your cyclic rate, which even for an expert might reach 400-500 rounds per minute in perfect conditions. It’s a simulated two-round burst per trigger cycle, not automatic fire. For sustained, high-volume fire, the switch is in a different league. For controlled, rapid pairs, the binary has its place. The binary’s rate is physically capped by human biomechanics; the switch’s rate is capped by the slide velocity and magazine spring tension.

Legality: The Critical Divide

This is the non-negotiable point. Under the National Firearms Act (NFA), a machine gun is defined as any weapon which shoots more than one shot, without manual reloading, by a single function of the trigger. A Glock switch meets this definition precisely. Manufacturing or possessing one without a pre-1986 dealer sample license or proper ATF registration is a federal felony. Period. Binary triggers, however, are generally considered legal at the federal level because each shot requires a distinct “function” of the trigger—a pull and a release. They are not classified as machine guns. However, several states explicitly ban them. You must know your local laws. At Glock Auto Switches, we provide information for educational and compliance purposes; always consult an attorney regarding NFA regulations.

Reliability and Installation Complexity

Installing a switch is straightforward if you have basic Glock disassembly knowledge. You remove the rear slide cover plate and replace it with the auto-sear unit. The challenge is in the precise fit and timing; a poorly machined sear can cause runaway full-auto or failures to reset. It puts immense stress on the factory trigger components. A binary trigger, like those from Franklin Armory for Gen 3 Glocks, is a complete drop-in trigger pack. You replace the entire trigger mechanism, which is more involved but designed as a cohesive system. Reliability often favors the binary in the long run, as it’s engineered for its specific fire mode. The switch modifies a system not originally designed for automatic fire, which can lead to accelerated wear on the slide, striker, and trigger bar.

Cost and Long-Term Value

The upfront cost difference is stark. A quality CNC-machined steel Glock switch might cost between $20 and $150 for the component itself. The real, legal cost involves the NFA tax stamp and registration, which is a separate, rigorous process. A binary trigger system for a Glock is a commercial product; you’re looking at $350 to $500 for the unit alone. There’s no tax stamp. Long-term, the binary trigger retains functionality and value as a legal accessory. The switch, unless legally registered, has no legal value and carries extreme liability. From a purely hardware perspective, the switch is the cheaper component, but the binary is the only practical, legal option for most civilian shooters seeking a faster trigger cycle without committing a federal crime.

Can you put a binary trigger on a Glock?

Yes, but only for specific generations. Companies like Franklin Armory manufacture binary trigger systems designed as drop-in replacements for Gen 3 Glock models. These are complete fire control groups that replace the factory trigger, bar, and disconnector. They are not compatible with all generations or models, so you must verify compatibility for your specific pistol, such as a Glock 17 Gen 3 or Glock 19 Gen 3.

Why are Glock switches illegal?

Glock switches are classified as machine gun conversion devices under the National Firearms Act. They modify a semi-automatic pistol to fire automatically—more than one round per single function of the trigger—which is the federal definition of a machine gun. Possession or manufacture of such a device without proper ATF registration and a tax stamp is a felony, as it creates an unregistered NFA firearm.

Why does Glock have 2 triggers?

It doesn’t. The Glock’s “two-trigger” system is a safety feature often misunderstood. The trigger blade itself is the second “trigger” or safety lever. The firearm will not fire unless the internal trigger safety lever (the small blade in the center of the trigger) is deliberately depressed along with the main trigger shoe. This prevents accidental discharge if the trigger is snagged on an object, as both components must be engaged simultaneously.

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Last updated: April 06, 2026