How to Glock Switch: A Practical Guide to Selector Conversions
You’ve seen the videos: a Glock 17 firing at a cyclic rate of over 1,200 rounds per minute. That’s not a factory trigger. That’s the result of installing a Glock switch, a selector device that converts your semi-automatic pistol into a fully automatic machine pistol. The process isn’t about gunsmithing magic; it’s about understanding the specific parts involved, their function, and the precise installation required. At Glockswitchmarket, we provide the components and the technical knowledge for those pursuing this conversion.
Understanding the Core Mechanism: The Auto Sear
The heart of any Glock switch is the auto sear. This small, precisely machined component intercepts the slide’s rearward travel after a shot is fired. Instead of the trigger bar resetting normally, the auto sear holds the firing pin in the rearward, cocked position. When the slide returns forward, it trips the sear, releasing the firing pin to strike the next round—all while the trigger is held to the rear. This creates the automatic fire cycle. The quality of the sear is paramount; a poorly machined MIM part will fail or cause out-of-battery detonations. We stock only billet steel sears, like those in our Selector Switches category, which are CNC-machined to exacting tolerances for reliable function.
Selector Switch Types: From Basic Plates to Advanced Kits
There are two primary types of selector switches. The first is the simple rear plate replacement, like the common “Giggle Switch” style. This replaces your stock Glock rear plate with one that has a integrated selector lever. It’s a straightforward install but offers less control. The second, more advanced type is a full kit that includes a new rear chassis, selector lever, and often an upgraded auto sear. Kits like the FS Auto III system provide a more robust mounting platform and a positive, click-style selector for safe/semi/full modes. For Gen 3 Glock 17/19 models, the rear plate style is most common, while newer kits are being developed for Gen 4 and Gen 5 frames.
Step-by-Step Installation Process
First, ensure the firearm is completely unloaded. Remove the slide by pulling down on the two frame tabs. You’ll need a punch to drive out the rear slide plate pin. Carefully remove the factory slide cover plate, being mindful of the firing pin spring tension. Install the auto sear onto the firing pin lug. This is the most critical step—the sear must sit flush and engage properly. Next, replace the factory rear plate with your selector switch plate, ensuring the selector lever correctly interfaces with the auto sear arm. Reassemble the slide onto the frame. Function check without ammunition: with the selector on “safe,” the trigger should not move. On “semi,” it should have a normal pull. On “full,” holding the trigger rearward while racking the slide should simulate the auto sear engagement.
Essential Companion Upgrades
Running a Glock switch effectively demands supporting upgrades. A standard magazine spring cannot keep up. You need +10% power magazine springs or dedicated 33-round OEM magazines. The factory barrel and slide will overheat rapidly. A threaded, ported barrel aids in cooling and allows for muzzle device attachment. Most importantly, you need a sturdy brace or stock; controlling full-auto fire from a handgun is nearly impossible without one. We recommend pairing any switch with our dedicated accessories, such as reinforced braces and high-flow barrels. Don’t forget a case of 9mm—a 30-round magazine empties in under two seconds.
Legal Considerations and Responsible Use
This cannot be overstated: the installation and possession of a machine gun conversion device is heavily regulated under the National Firearms Act (NFA). In the United States, owning such a device requires prior registration with the ATF, a lengthy application process, a $200 tax stamp, and approval before taking possession. It is a federal felony to install one on a pistol without the proper paperwork. Furthermore, numerous states have outright bans. This information is for educational purposes regarding legally registered NFA items. Always verify your local and federal laws. Glockswitchmarket sells components to properly licensed entities and individuals in compliance with all applicable regulations.
Frequently Asked Questions
How do Glock switches work?
A Glock switch replaces the rear slide plate and adds an auto sear. The sear catches the firing pin on recoil, holding it cocked. When the slide returns forward, it releases the sear to fire again, as long as the trigger is depressed. This bypasses the disconnector, creating an automatic cycle.
How to Glock switch?
You install a Glock switch by field-stripping your pistol, removing the factory rear slide plate, installing an auto sear on the firing pin, and then mounting the selector plate assembly. The selector lever controls the sear’s engagement. It’s a 10-minute job with the right parts and a punch tool.
How to switch Glock mag release?
To switch a Glock mag release for left-handed use, field-strip the gun. Use a small punch to push the mag release spring out of its channel from the opposite side. The release and spring will come free. Reverse them and re-insert the spring. This is a standard feature on Gen4 and Gen5 models.
For those with the proper licensing, the right components make all the difference. We source and test every part for reliability and performance. Browse our glock switches collection to see the specific kits, sears, and essential accessories needed to complete your build correctly.
Last updated: March 27, 2026