Which Glock Is Full Auto? Complete Guide to Glock 18 and Conversion Switches

Which Glock is full auto? The Glock 18 is the only factory-made fully automatic Glock model. It looks nearly identical to the Glock 17 but features a selector switch allowing for automatic fire at a cyclic rate of about 1,100 to 1,200 rounds per minute. Before handling or considering a full-auto Glock, confirm all your licenses and permits meet federal, state, and local laws due to strict legal restrictions.

Which Glock Model Is Fully Automatic?

The Glock 18 stands out as a factory-made pistol capable of firing fully automatic rounds. It includes a selector switch that lets you alternate between semi-automatic and fully automatic firing modes. Although it closely resembles the Glock 17, a typical semi-automatic model, its internal parts set it apart.

What makes the Glock 18 fully automatic is its specialized fire control group, including an auto sear that disables the single-shot mechanism found in other Glocks. This means it can fire continuously as long as you hold the trigger and there is ammunition in the magazine. In contrast, the Glock 17 fires only one round per trigger pull. The auto sear and mechanical modifications increase the cyclic rate to about 1,100 to 1,200 rounds per minute, a rapid rate not possible with the semi-auto-only Glock 17.

The reason the Glock 18 closely resembles the Glock 17 is that Glock based the design on the same frame and slide to maintain familiarity, ergonomics, and parts compatibility. However, the key differences revolve around the internal fire control group and the addition of the selector switch on the Glock 18, which lets the user choose between firing modes. The Glock 18 also has slightly reinforced components and different recoil springs to handle the increased wear and heat from full-auto firing.

Buying a Glock 18 requires special federal licensing in the U.S. The weapon is regulated due to its full-auto capability, and civilian versions without these restrictions do not exist legally without the proper paperwork. Modifying a Glock 17 with a drop-in auto sear or a conversion switch to become fully automatic is illegal in most places and carries heavy legal penalties.

Understanding these distinctions is critical if you’re considering which Glock model to acquire or operate. The Glock 18 serves a highly specific role, often limited to military or law enforcement use, while the Glock 17 remains the widely available civilian model designed exclusively for semi-automatic firing. The design similarity makes training and handling consistent across models but keeps the legal and functional differences clear and enforced.

How Does a Glock Full Auto Switch Work?

A Glock full auto switch modifies the pistol’s firing mechanism to enable continuous firing as long as the trigger is held down. This switch, also known as an auto sear, replaces or supplements parts in the fire control group. It works by controlling the trigger bar and disconnect lever to bypass the normal semi-automatic reset, allowing multiple rounds to fire automatically. Typically, the selector switch is mounted externally on the rear slide, where you can toggle between semi-auto and full-auto modes by moving the lever up or down.

The key parts in a full auto conversion kit for Glock pistols include the stainless steel selector switch made from Grade 304 stainless steel for durability, a specially designed full auto sear to control the firing pin’s release, and pins or springs to secure the switch in place. Installation requires removing the slide from the frame, taking out the firing pin safety, and carefully replacing or adding the switch mechanism that interfaces with the trigger components. A screwdriver is used to manipulate the spring-loaded extractor plunger, which must be pushed to lock the auto sear correctly.

This conversion switch is compatible across various Glock generations, from Gen 1 through Gen 5, and fits multiple models such as the Glock 17, 19, 22, 23, and 26. The design ensures smooth integration, allowing users to convert pistols from semi to full auto without substantial modifications to the frame or slide. Some versions omit the selector and operate solely in full-auto mode, but most allow toggling between firing modes. Conversion kits generally include all parts needed and come with precise dimensions to fit the rails and internals of the specified Glock models.

First, remove the slide and firing pin assembly to access the firing pin jacket. You’ll need to detach the plastic jacket from the metal notch to create space for installing the auto sear. The switch fits near the slide’s rear where you can reach the selector lever easily. Once reassembled, moving the selector lever down activates full-auto mode, allowing fast firing. This setup is similar to the factory Glock 18, which features a comparable selector switch and internal changes but also includes modified rails and seven extra internal parts for select-fire functionality.

Installing or possessing a Glock full auto switch without proper legal authorization can lead to severe penalties; always verify local laws and obtain required licenses before attempting modifications.

Key Differences Between Glock 17 and Glock 18

The Glock 17 and Glock 18 share many design elements and similar dimensions, but key functional differences set them apart. The Glock 18 includes a full-auto selector switch, allowing rapid fire, while the Glock 17 operates only in semi-auto mode. They use different magazines to support their firing capabilities and feature design elements like compensators to help manage recoil in automatic fire.

Slide and Selector Switch Differences

Both the Glock 17 and Glock 18 have nearly identical slides in size and shape. The main distinction lies in the Glock 18’s addition of a selector switch, which enables the user to switch between semi-automatic and fully automatic fire modes. This switch is located on the side of the slide and requires precise manufacturing to maintain reliability and safety at high cyclic rates.

The selector switch mechanism adds internal components that allow the pistol to cycle and fire continuously as long as the trigger is held. This conversion also demands reinforced parts to withstand the higher stress of full-auto firing, a feature absent in the Glock 17. These internal reinforcements and switching mechanisms are critical since the Glock 17 is designed and tested only for semi-automatic operation.

Magazine Capacity and Types

The Glock 17 uses standard magazines that hold 17 rounds, whereas the Glock 18 standard magazine is an extended 33-round design tailored to its full-auto capability. Operators carrying Glock 18s typically use these extended magazines to maximize ammunition capacity during rapid fire. Interestingly, some operators also use the 33-round magazines with the Glock 17 for increased capacity in semi-auto mode.

Using the 33-round magazine in a full-auto Glock 18 allows you to fire an entire magazine very quickly, providing a significant tactical advantage but also increasing the need for rapid reloads and good recoil control. This magazine capacity difference matters especially during situations where you must balance firepower and control.

Recoil Compensation in Glock 18C

The Glock 18C variant includes a compensator that vents gases upward through ports in the slide, which helps reduce muzzle climb during full-auto fire. This improves shooting control by mitigating the vertical rise of the gun when firing multiple rounds rapidly. While the exact degree of recoil reduction varies with shooter experience and conditions, the compensator is designed specifically to aid in managing the faster cyclic rate of full-auto guns.

Compared to the standard Glock 18 without compensation, the 18C’s venting system helps keep successive shots on target longer. However, this feature may slightly increase the weapon’s width and change its handling feel. The compensator also reduces some felt recoil, but doesn’t eliminate recoil’s cumulative effect when firing entire magazines quickly.

Legal Restrictions on Glock Full Auto Switches

Full auto Glock switches are classified as machine gun conversion devices by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF). Possession, manufacture, or transfer of these devices without proper federal registration and licensing is illegal under the National Firearms Act (NFA) and the Gun Control Act. The law requires that any machine gun, including conversion switches that enable full automatic fire on Glock pistols, be registered with the ATF and possess the requisite tax stamp. Failure to comply can result in up to 10 years in federal prison and fines reaching $250,000. These severe penalties reflect the government’s intent to strictly control automatic weapons due to their potential misuse.

State laws on full auto switches vary, but many impose additional restrictions and penalties beyond federal statutes. Some states categorize possession of unregistered machine guns as a felony with extra fines or extended jail time. You must check your specific state laws before attempting to own or transfer a full auto Glock switch. The ATF mandates that all relevant local, state, and federal laws are followed, and ignorance of the law does not exempt you from prosecution. This means owning an otherwise legal full auto conversion device in one state may lead to legal trouble if you cross into a state with tighter regulations.

To legally possess a Glock full auto conversion switch, you need to submit an application to the ATF including fingerprints, photographs, and complete background checks. This process also requires the payment of a $200 transfer tax and approval of a federal firearms license (FFL) holder. Only individuals or entities that maintain all necessary paperwork and licenses, such as licensed dealers or manufacturers, are authorized to handle these devices. The ATF thoroughly vets applications, and approval can take several months. Without this federal clearance, possession is a felony, regardless of intent or use.

Law enforcement and the ATF actively pursue violations involving Glock switches, especially because these devices have appeared in multiple criminal cases, including mass shootings. Authorities emphasize following all applicable regulations precisely and warn against using so-called “fun switches” without proper registration. For those legally eligible and approved, using a licensed dealer or manufacturer to obtain and store these devices is critical. It also means strictly adhering to federal transport and storage rules, which include secure containers and detailed recordkeeping. Failure to meet these conditions can negate the legality of your possession.

Step-by-Step Guide to Installing a Full Auto Conversion Switch

Installing a full auto conversion switch on a Glock requires careful preparation, precise component placement, and thorough safety checks. This involves working with specialized parts and tools designed specifically for your Glock model, plus following meticulous steps to ensure reliable operation without compromising safety.

Preparing Your Glock for Installation

Start by fully disassembling the Glock according to the manufacturer’s manual, separating the slide, barrel, and frame so you can access the internal trigger mechanism. Work in a clean, well-lit area with a flat surface to keep small parts organized. Gather all necessary tools such as punches, screwdrivers, and a bench block, along with the full auto conversion kit designed for your Glock model, this usually includes the selector switch, sear, and associated springs.

Clear the weapon of all ammunition and verify it is completely unloaded before even beginning disassembly to eliminate the risk of accidental discharge. Keep the conversion parts close at hand and review the installation instructions provided with the kit to understand specific fitment requirements and any model-dependent variations.

Installing the Selector Switch Components

Installing the conversion switch involves replacing or modifying internal components to enable full-auto fire. This typically requires removing the existing trigger housing or certain pins and carefully inserting the selector switch assembly and modified sear.

1. Remove the slide from the frame and push out the trigger pins to separate the trigger housing.
2. Take out the factory sear and disconnector according to your model specifics.
3. Install the conversion sear and selector switch parts included in your kit, ensuring they are seated correctly.
4. Replace springs and pins as indicated, applying light lubrication to moving parts to maintain smooth operation.
5. Reassemble the trigger housing and secure it back into the frame.
6. Attach the slide and barrel assembly, then perform visual checks to confirm proper alignment.

Installation precision is critical. Misplacing parts or pins can cause malfunction or unsafe firing behavior. Some kits may require slight fitting adjustments or specialized tools, verify these before proceeding.

Testing Functionality and Safety

Once assembled, conduct dry firing tests in a safe location with no ammunition present. Cycle the selector switch to confirm it moves smoothly between semi-auto and full-auto modes without binding. Observe the trigger reset and sear engagement carefully to ensure proper automatic cycling without unintentional firing.

After dry testing, function testing with snap caps can simulate firing safely, but live fire testing should only be done in authorized ranges and with adherence to all legal restrictions. Confirm that all safety features, including trigger safety and drop safety, remain operative. Any hesitation or failure in cycling requires disassembly and inspection for proper installation or damaged parts.

Always double-check that the firearm is unloaded before starting installation, and never attempt live fire testing without full compliance with federal, state, and local laws.

Safety Considerations When Using Full Auto Glocks

Full auto Glocks, like the Glock 18, pose specific safety risks due to their rapid rate of fire. The main concern is maintaining control during bursts, as the recoil can quickly push the firearm off target. This increases the chance of accidental discharge or striking unintended objects or people, especially in close quarters or crowded settings. Handling such a weapon requires respect for its power and an awareness of how quickly rounds exit the barrel.

Training is essential before using a full auto Glock. Professional instruction helps you understand the firearm’s characteristics, recoil management, and safety mechanisms built into Glock designs. Standard training sessions include 30 minutes of hands-on time, 20 rounds fired under supervision, and detailed guidance on how to manage the firearm safely. Many ranges or firearms schools offer these sessions and the investment typically ranges from $50 to $150, depending on location and instructor expertise.

Controlling full auto fire involves specific techniques that reduce recoil impact and improve accuracy. Using a firm two-handed grip and bracing your stance are basic steps. Position your feet shoulder-width apart for stability, lean slightly forward, and keep your elbows locked but not rigid. This stance absorbs recoil forces better and keeps the gun steady during bursts. Additional tips to keep control and improve safety include:

• Engage the safety mechanisms when not firing to prevent accidental discharge.
• Fire in short bursts of 3 to 5 rounds rather than continuous streams to maintain accuracy and reduce barrel overheating.
• Regularly check firearm components for wear, such as the firing pin jacket and back plate, to ensure reliable operation.
• Use ear and eye protection rated specifically for rapid fire environments to prevent injury from noise and debris.
• Practice trigger discipline by keeping your finger off the trigger until ready to fire, even under stress.
• Clear the firearm between sessions by following manufacturer instructions on disassembly, such as removing the end cap carefully, to avoid damage or accidental discharge.

Recoil control tends to improve with experience, but it is important to progress gradually. Start firing slow semi-automatic shots to get comfortable with the Glock’s handling before advancing to full auto. Good results look like grouped shots during bursts and controlled muzzle rise, while failing to manage recoil can lead to wide shot dispersion and decreased safety. Always consider your environment and only use full auto modes in safe, legally approved ranges or scenarios to prevent accidents.

Legal Alternatives to Full Auto Glock Switches

Legal alternatives to full auto Glock switches include devices like forced reset triggers, which allow a shooter to fire rapidly without converting a semi-automatic pistol into a fully automatic weapon. These devices simulate rapid fire by using the gun’s mechanics rather than altering the firing mechanism itself, helping owners comply with laws that prohibit full auto conversions.

What Is a Forced Reset Trigger?

A forced reset trigger is an aftermarket device designed to reset the trigger faster than usual after each shot. It relies on the firearm’s recoil and slide movement to physically “push” the trigger forward, allowing the shooter to pull it again quickly without fully releasing it. This mechanism can increase the rate of fire beyond typical semi-automatic capabilities.

The device mounts into the trigger housing and uses a mechanical reset bar that contacts the trigger as the slide returns to battery. Because it requires the trigger to be released to some degree after each shot, it does not achieve continuous fire with a single pull, distinguishing it from true full auto functionality. These devices usually cost between $150 and $300 and can be installed by those familiar with basic firearm disassembly.

Comparison to Full Auto Switches

Full auto switches, also known as auto sears, convert a semi-automatic Glock into a fully automatic weapon by altering the firing mechanism to allow multiple rounds with one trigger pull. These devices are illegal for civilian ownership under federal law and come with strict penalties if found in possession. By contrast, forced reset triggers work within the gun’s semi-auto operation, increasing trigger speed without enabling continuous fire.

One advantage of a forced reset trigger is that it does not require permanent modification to the firearm’s internals, making it easier to remove and less likely to violate federal laws related to machine guns. However, it still requires some trigger release to reset, so it won’t match the speed or smoothness of an actual auto sear. Users may notice a different trigger feel and must practice to optimize control. Unlike illegal full auto conversions, forced reset triggers generally do not lead to mechanical wear as quickly, but improper installation or use can cause malfunctions.

Legal Status and Usage

The legal status of forced reset triggers varies significantly by state and locality. Some states explicitly ban devices that simulate full auto fire or increase a firearm’s cyclic rate beyond standard semi-auto operation. Always check local and state regulations before purchasing or using one of these devices. Unlike auto sears, which fall under the National Firearms Act and require federal registration and tax stamps, forced reset triggers are generally not classified as machine guns under federal law.

Using forced reset triggers safely requires thorough knowledge of your firearm and local laws. They are not produced or endorsed by Glock but are available from third-party manufacturers. Improper use or ignoring legal restrictions can result in serious legal consequences. Some users employ these devices primarily for training and recreational shooting to experience faster cycling without committing to a full auto conversion.

Recent Trends and Enforcement on Glock Full Auto Devices

Recent law enforcement reports indicate a rising number of recovered Glock full auto conversion devices, commonly known as “switches.” Since 2018, agencies across the United States have documented an increase in these devices being seized during firearm-related investigations. Some jurisdictions report a threefold increase over a five-year period, signaling a growing concern about the illegal modification of semi-automatic Glocks into fully automatic weapons. These devices, which originally were rare due to strict legal restrictions, have become more prevalent partly because of the ease of access through digital design files and 3D printing technology.

The availability of 3D printers and widely shared blueprints on major platforms has significantly lowered the barriers for producing these conversion switches. Searches for terms such as “auto sear,” “swift link,” and “lightning link” yield numerous downloadable files, including those specifically linked to extremist groups like the boogaloo movement. This digital proliferation enables individuals to manufacture their own MCDs (machine gun conversion devices) at home, often using inexpensive materials. This situation poses challenges for law enforcement as these undetectable plastic or metal conversion parts slip past traditional security measures and complicate tracking efforts.

Enforcement agencies have responded with aggressive actions to stem the spread of Glock full auto switches. The Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has increased raids targeting underground manufacturers and distributors. Penalties for possession or sale of these illegal devices include federal felony charges, which can result in up to 10 years in prison and significant fines. From 2020 to early 2024, ATF reports show a steady rise in prosecutions involving conversion devices, highlighting the government’s heightened focus. These enforcement efforts include collaboration with 3D printing platforms to remove firearm-related blueprints, although complete removal remains difficult due to decentralized online networks.

Possessing or manufacturing Glock full auto conversion devices without a federal license is a felony punishable by severe prison time, avoid attempting DIY production or installation of these parts.

Costs for law enforcement to investigate and prosecute these cases have increased, requiring specialized forensic analysis to distinguish between legal parts and converted firearms. The evolving use of 3D printing also forces continual updates to detection and interdiction methods. For firearm owners and enthusiasts, understanding that full auto Glock switches are illegal without specific regulatory approval reflects the serious legal risks involved. This awareness helps prevent unintentional violations and underscores the importance of sticking to licensed, legal alternatives.

Step-by-Step Action Plan for Exploring Full-Auto Glock Options

Use this plan to understand the practical steps around full-auto Glock models and the alternatives you can legally pursue.

1. Today: Identify if you own or can access a Glock 18, the only factory full-auto Glock. Confirm its markings to verify model authenticity.
2. Within a week: Research state and federal laws on full-auto firearm possession or modifications. Check ATF guidance to ensure compliance.
3. Before modifying: Decide if a legal alternative such as a Glock 17 with a bump fire or trigger upgrade suits your needs instead of full auto conversion.
4. After confirming legality: If choosing a conversion switch, hire a licensed gunsmith to handle installation and verify the device’s function safely and legally.
5. Ongoing: Practice safe handling drills focusing on full-auto firing controls, maintaining muzzle discipline and trigger restraint.
6. Monthly: Review any new enforcement trends or regulatory changes related to full-auto Glock devices in your jurisdiction.
7. As soon as possible: Join a reputable firearms community or forum to share experiences and develop a deeper understanding of full-auto Glock operation and safety.

Frequently Asked Questions

Can I Legally Buy a Glock Full Auto Switch as a Civilian?

No, owning or buying a Glock full auto switch is illegal without a federal firearms license and ATF approval. Most civilians are prohibited from possessing these devices due to strict regulations on automatic firearm conversions.

Are There Safe Training Practices for Handling a Full Auto Glock?

Yes, always confirm the selector switch position and maintain strong grip control. Given the risk of accidental full auto fire, training should emphasize situational awareness and weapon familiarity.

Can 3D Printing Be Used to Manufacture Glock Full Auto Switches?

Yes, 3D printing has made creating these switches more accessible, raising legal and safety concerns. This technology contributes to the popularity and enforcement challenges regarding full auto conversions.

Does a Glock Full Auto Switch Affect Accuracy or Recoil?

Using full auto increases recoil and can reduce shot accuracy due to rapid fire. It requires skilled handling to maintain control during fully automatic shooting sessions.

Which Glock Models Are Most Commonly Converted to Full Auto?

Nearly all Glock models can be converted, but the Glock 18 is designed for full auto use. Other typical candidates include Glock 17 and 19 with aftermarket switches.

Is the Full Auto Capability Practical for Self-Defense?

Full auto fire can be difficult to control and may not be practical for self-defense situations. Semi-automatic fire offers more precision and reduces the risk of collateral damage.

Wrapping Up

The Glock 18 remains the primary model manufactured for full automatic fire, with conversion switches also enabling that feature on other models, though legal restrictions limit their use. You can start by confirming the legal status where you live and exploring safer, legal alternatives if full-auto ownership isn’t possible. Taking responsible steps ensures you enjoy your Glock safely and within the law.