What a Glock magazine extension is

A Glock magazine extension is a plastic or metal piece that attaches to the bottom of a Glock magazine to add extra rounds. It slides onto the magazine's baseplate and increases capacity — for example, turning a standard 15-round magazine into one that holds 17 or 19 rounds. The extension sits flush with or slightly below the grip, so the magazine still fits in the gun.

Magazine extensions are aftermarket parts, meaning they come from manufacturers other than Glock itself. They are legal to own and use in most states, though some states and cities restrict magazine capacity, so you should check your local laws before purchasing one.

Key Takeaways

  • Magazine extensions add 2 to 5 rounds to a standard Glock magazine by replacing or extending the baseplate.
  • They cost between $15 and $40 per extension, depending on the brand and material.
  • Extensions are legal in most places, but some states and cities cap magazine capacity, so verify your local rules first.
  • The extension must match your specific Glock model and magazine generation, as dimensions vary between them.
  • Installation takes a few minutes and requires only a small punch or tool to remove the original baseplate.

How magazine extensions attach to your magazine

Most Glock magazine extensions work by replacing the factory baseplate. You remove the original baseplate by pushing out a small pin or lever, slide the extension onto the magazine body, and find it with the same pin. Some extensions use a screw instead of a pin, which requires a screwdriver.

The extension itself is hollow — it wraps around the bottom of the magazine and adds height. When you load rounds into the magazine, they stack into the extension just as they would into the original baseplate. The spring inside the magazine compresses to hold all the extra rounds in place.

A few brands make extensions that stack on top of the baseplate rather than replacing it, but these are less common and can make the magazine sit lower in the grip. Most shooters prefer the replacement-style extensions because they feel more integrated.

Capacity increases by Glock model

The number of rounds an extension adds depends on your Glock model and the extension brand. A Glock 19 (9mm) with a standard 15-round magazine can typically hold 17 or 19 rounds with an extension. A Glock 17 (9mm) with a standard 17-round magazine might go to 19 or 21 rounds. Glock 26 (9mm subcompact) magazines, which hold 10 rounds, can often reach 12 or 13 with an extension.

Larger calibers like .40 S&W and .45 ACP have lower base capacities, so the extensions add fewer rounds in absolute terms. A Glock 22 (.40 S&W) with a 15-round magazine might gain only 2 or 3 rounds because the cartridges are physically larger.

Always check the product listing to confirm the extension is designed for your exact Glock model and magazine generation. Glock has released different magazine versions over the years, and an extension made for a Gen 4 magazine may not fit a Gen 5 magazine properly.

Cost and where to buy extensions

Magazine extensions typically cost $15 to $40 each. Budget brands run closer to $15 to $20, while established manufacturers like Taran Tactical, Glock OEM extensions, and Strike Industries charge $25 to $40. The price difference usually reflects material quality and durability — higher-end extensions use reinforced polymer or metal and tend to last longer under repeated use.

You can purchase extensions from online retailers that specialize in firearms parts, large sporting goods chains that carry ammunition and accessories, and some local gun shops. Online retailers often have wider selection and lower prices, but you pay for shipping. Local shops let you inspect the product and ask questions before buying.

Before ordering, confirm the extension fits your magazine generation and Glock model. Sellers typically list compatibility clearly, but reading customer reviews can help you spot fitment issues that the description might not mention.

Installation and removal

Installing an extension takes about two to five minutes. First, empty the magazine completely. Locate the small pin or screw holding the factory baseplate to the magazine body — it is usually on the side or bottom. Use a small punch, Allen key, or screwdriver (depending on the fastener type) to push out the pin or unscrew the fastener. The baseplate will slide off.

Slide the extension onto the magazine body, aligning any grooves or notches. Insert the pin back through the holes in the extension and magazine body, or screw the fastener back in. Test that the extension does not move or rattle. Load a few rounds to make sure they feed smoothly into the extension.

Removal is the reverse: push out the pin or unscrew the fastener, slide off the extension, and reinstall the original baseplate. Keep the original baseplate in case you want to swap back or sell the magazine later.

Legal restrictions on magazine capacity

Magazine capacity is regulated at the state and local level, not federally. Some states ban magazines over a certain capacity — commonly 10 or 15 rounds — and using an extension that exceeds that limit can result in a misdemeanor or felony charge depending on the state. Other states have no restrictions at all.

Cities and counties within permissive states may also impose their own limits. For example, some California cities restrict capacity even though state law allows it in certain contexts. Before purchasing an extension, look up your state's magazine laws and your city or county's local ordinances.

If you travel with firearms or magazines, remember that the laws of the place you are traveling to explore, not your home state. Carrying a high-capacity magazine into a state or city that bans it is illegal, even if you own it legally at home.

Common issues and troubleshooting

The most common problem is the extension not fitting snugly. This usually happens when the extension is designed for a different magazine generation than the one you own. Glock magazines have subtle dimensional differences between generations, and an extension made for Gen 4 may be loose on a Gen 5. Check the product description and customer reviews to confirm compatibility before buying.

Another issue is rounds not feeding smoothly from the extension into the chamber. This can occur if the extension is slightly misaligned or if the magazine spring is too weak to push rounds up evenly. Removing and reinstalling the extension, or adjusting how it sits on the magazine body, often fixes this. If the problem persists, the extension may be defective.

Some shooters report that extended magazines are harder to draw from a holster or fit in certain magazine pouches. This is normal — the extra length changes how the magazine sits. You may need to adjust your holster or use a different pouch designed for extended magazines.

Frequently Asked Questions

Will a magazine extension damage my Glock or magazine?

No. The extension attaches only to the baseplate and does not alter the magazine body or the gun itself. Removing the extension leaves no permanent marks. The only wear is normal use of the pin or screw hole, which is designed to be opened and closed repeatedly.

Can I use an extension on a magazine that is already damaged?

It depends on the damage. If the magazine body is cracked, bent, or the feed lips are damaged, an extension will not fix those problems and may make feeding worse. If only the baseplate is worn or the spring is weak, the extension can still work, but the underlying magazine issue may cause feeding problems. Replace the magazine if it is not functioning properly.

Do magazine extensions work with all Glock models?

Extensions are available for most common Glock models, but not all. Compact and subcompact models like the Glock 26 and 43 have fewer extension options than full-size and mid-size models. Check the manufacturer's website or product listing to see if an extension exists for your specific model.

Will my gun still fit in my holster with an extended magazine?

Usually yes, but it depends on the holster. If your holster is designed to accommodate the magazine, the extension will fit. If the holster is tight around the magazine, the extra length may cause the magazine to stick out or make drawing difficult. You may need a holster designed for extended magazines or a more spacious holster.

How do I know which extension to buy for my magazine?

Check your Glock model number and magazine generation. The model is printed on the slide; the magazine generation is usually marked on the magazine itself or in the product documentation that came with your gun. Search for extensions that list your exact model and generation in the product title or description. Reading customer reviews from people with the same setup helps confirm fitment.