Glock Switch vs. FRT: A Direct Comparison of Two Different Systems

You’re at the bench with a stripped Glock slide in front of you, and you’re weighing your options for a transformative upgrade. The debate often comes down to two distinct paths: installing a dedicated auto sear, commonly called a Glock switch, or integrating a forced reset trigger (FRT) like the Rare Breed FRT-15. One is a direct, mechanical modification to the firearm’s core; the other is a clever trigger assembly that exploits the firearm’s cycle of operation. Understanding the fundamental mechanical and legal differences between these systems isn’t just academic—it dictates your build, your performance, and your compliance strategy.

Core Mechanical Operation: Internal Sear vs. Trigger Mechanism

The difference starts at the component level. A Glock switch, such as the common “Giggle Switch” or “Auto Key Card” style sears we stock, is a small, precision-machined part that replaces or modifies the factory rear housing plate. Its job is to physically catch and release the striker on every shot, turning the semi-automatic action into a fully automatic one. It’s an internal modification that interacts directly with the fire control group. An FRT, in contrast, is a complete drop-in trigger unit. It uses a proprietary disconnector and spring system to force the trigger forward and “reset” it the instant the bolt carrier group travels rearward after firing, allowing for an incredibly rapid rate of fire without a traditional auto sear. The Glock switch *creates* automatic fire; the FRT *simulates* it through mechanical forced reset.

Platform Compatibility and Installation Complexity

Your choice of platform locks you in. A Glock switch is designed specifically for Glock pistols—models like the G17, G19, and G26. You need a compatible lower receiver (the pistol frame) and the technical know-how to properly install the sear, often involving careful fitting and understanding of the FCU. At Glockfullautoswitches, our Glock switches category includes options for various Gen 3-5 models. The FRT-15, however, is built for the AR-15 platform. It’s a true drop-in unit for a standard mil-spec lower, requiring no permanent modification. You simply remove your old trigger group and install the FRT. So, your decision is binary: are you building a switch-equipped Glock or an FRT-equipped rifle?

Performance and Practical Function

On the range, the experiences diverge. A properly installed Glock switch provides authentic, select-fire functionality. With a quality switch like the ones we vet at Glockfullautoswitches, you get reliable, consistent full-auto performance from a compact platform, though controllability is a learned skill. The FRT-15 offers a phenomenally high rate of fire—often matching or exceeding that of a binary trigger—but it is not full-auto. It requires a consistent, maintained rearward pressure on the trigger; release the pressure, and firing stops. This “reset” action can feel different from a traditional pull. For pure, unadulterated automatic fire from a handgun, the switch is the only mechanical answer.

Legal Status and Critical Considerations

This is the non-negotiable section. Under the National Firearms Act (NFA), a machine gun is defined by its ability to fire more than one cartridge per single function of the trigger. A Glock switch meets this definition unequivocally. Possession of one not registered in the NFA registry is a federal felony. The FRT-15 exists in a contested gray area. The ATF initially approved it, then reclassified it as a machine gun, leading to seizures and legal battles. While some courts have recently ruled against the ATF’s classification, its status remains volatile and legally risky. Purchasing any item from our store requires you to understand and comply with all federal, state, and local laws. We are a parts supplier for qualified entities only.

Making the Informed Choice for Your Build

Your decision matrix should be clear. Choose a Glock switch if you are a qualified manufacturer (SOT) building a registered machine gun on a Form 1 or Form 2, or are working within other strict legal confines, and you want authentic automatic fire from your Glock pistol. You are committing to a platform-specific, internal modification. Opt for an FRT-style trigger if you are building on an AR-15 platform, understand the ongoing legal uncertainty, and seek the fastest possible semi-auto rate of fire from a drop-in trigger without a tax-stamped lower. For those proceeding legally with a Glock build, selecting a reliable component is paramount. We stand behind the fit and function of the switches in our store for those with the proper credentials.

What is a switch for a Glock?

A Glock switch is a small, aftermarket auto sear component that modifies the firearm’s fire control group. When installed, it converts a standard semi-automatic Glock pistol into a fully automatic machine gun by mechanically controlling the release of the striker. It is legally classified as a machine gun under the NFA.

Is an FRT the same as a Glock switch?

No, they are fundamentally different. An FRT (Forced Reset Trigger) is a drop-in assembly for rifles like the AR-15 that uses a forced mechanical reset to enable rapid fire. A Glock switch is a specific internal part for Glock pistols that acts as an auto sear to create true automatic fire. They work on different platforms and through different mechanical principles.

Which one has a faster rate of fire?

In practical terms, a high-quality FRT-15 in an AR-15 can achieve an extremely high cyclic rate, often cited around 900 rounds per minute, due to its forced reset mechanism. A Glock switch on a pistol like a G17 typically cycles around 1,200-1,400 RPM. However, the pistol’s smaller platform makes sustaining that theoretical rate and maintaining control significantly more challenging.

Are these items legal to own?

The legal status is complex and strict. An unregistered Glock switch is always illegal for civilian possession under federal law. The FRT-15 is currently the subject of ongoing litigation after the ATF classified it as a machine gun. Ownership of either by a non-licensee carries severe federal felony penalties. Always consult with a firearms attorney to ensure full compliance.

For qualified professionals and manufacturers operating within the bounds of federal law, selecting the right component is the foundation of a reliable build. If your project requires a precision-machined Glock switch for a registered NFA firearm, we invite you to browse our Glock switches collection and see the difference quality components make.

Last updated: March 25, 2026