What Do Glock Switches Do? The Technical Reality of Selector Switches
A standard Glock 19 fires one round per trigger pull. Install a small, aftermarket component often called a “switch,” and that same pistol can empty its entire 15-round magazine in under two seconds. This isn’t movie magic; it’s a mechanical conversion that fundamentally alters the firearm’s function. At Glockautoswitches, we provide the components for this conversion, and it’s critical to understand exactly what you’re working with from a technical and legal standpoint.
The Core Function: Converting from Semi-Auto to Full-Auto
A Glock switch, formally known as an auto sear or selector switch, replaces a single internal component—the rear plate cover—on most Gen 3-5 models. Its job is to mechanically interrupt the pistol’s disconnector function. In a stock Glock, the slide’s rearward travel resets the trigger via the disconnector. The switch holds the disconnector down, preventing this reset and allowing the firing pin to strike the next round as long as the trigger is held rearward and there is ammunition in the magazine. This creates an open-bolt, blowback-style full-auto operation. The rate of fire is exceptionally high, often cited between 1,200 and 1,500 rounds per minute, which is why we strongly recommend pairing these devices with a stock or brace for any semblance of control.
Key Components and Installation
The device itself is typically a CNC-machined block, often made from 7075 aluminum or steel, that houses a pivoting sear and a selector lever. Installation doesn’t require permanent modification to the frame. You field-strip the pistol, remove the factory rear cover plate, and install the switch unit in its place, securing it with its provided pin. The selector lever usually has two positions: “S” for semi-auto (which functionally disengages the auto sear) and “F” for full-auto. It’s a simple mechanical process, but it requires understanding your specific Glock model. For example, our Glock 17/19/26 Gen 3-5 Switch is designed for the common 9mm double-stack models, while dedicated units are needed for .40 cal or Gen 1-2 frames.
Performance and Practical Implications
In practical terms, the performance is transformative and demanding. The cyclic rate means a standard 17-round magazine is empty in roughly one second. Recoil impulse is straight back into the web of your hand, making muzzle climb severe and sustained aimed fire nearly impossible without a stabilizing attachment. Ammunition consumption becomes a primary logistical and financial concern. These are not devices for precision; they are for delivering a high volume of fire in an extremely short time frame. For those building a dedicated platform, we recommend viewing our full-auto parts kits to ensure you have all necessary supporting components.
Legal Status and Critical Disclaimer
It is imperative to state this clearly: Under the National Firearms Act (NFA) of 1934, 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 equipped with a switch meets this definition. Manufacturing or possessing one without the proper federal licensing—specifically, a Class 3 Special Occupational Tax (SOT) for manufacturers/dealers, or an approved Form 1 tax stamp for individuals—is a felony punishable by up to 10 years in prison and $250,000 in fines. Glockautoswitches sells these components solely to qualified SOT holders and entities for whom they are legal. End-users are 100% responsible for compliance with all federal, state, and local laws.
Choosing the Right Platform and Parts
Not all Glocks are ideal hosts. Full-auto fire dramatically increases wear on the slide, barrel, and locking block. A robust Gen 3 or Gen 4 Glock 17 in 9mm is the most common and proven platform due to parts availability and durability. Using a switch on a subcompact like a Glock 26 is possible but offers even less control. Beyond the switch itself, a quality extended magazine (33-round or drum) is a practical necessity, and a compensated or ported barrel can help marginally with muzzle rise. Remember, this conversion turns your reliable sidearm into a high-stress machine that will require more frequent maintenance and part replacement.
What do Glock switches do?
A Glock switch is an auto sear that mechanically alters the pistol’s fire control group. It disables the disconnector, allowing the firearm to continue firing as long as the trigger is held down, converting it from semi-automatic to fully automatic fire. This results in a very high rate of fire, typically over 1,200 rounds per minute.
Why are Glock switches illegal?
They are classified as machine gun conversion devices under the National Firearms Act (NFA). Possession or installation of one on a firearm, without prior registration and approval from the ATF via a tax stamp, constitutes the illegal manufacture of a machine gun. This is a federal felony with severe penalties.
What is a Glock with a switch?
A Glock with a switch installed is legally defined as a machine gun. It is a modified pistol capable of fully automatic fire. The physical device is a small aftermarket component that replaces the rear cover plate, containing a sear and selector lever to enable this function.
For qualified professionals and entities operating under the appropriate federal licenses, Glockautoswitches offers a selection of precision-machined components. Browse our glock switches collection to see our current inventory of auto sears and supporting accessories.
Last updated: March 27, 2026