Glock Mag Compatibility: What to Know

Glock Mag Compatibility: What to Know

6th Jun 2025

Some of the most common questions about Glock mags have expressly to do with cross-compatibility. Let this short post serve as a resource on that matter.

About Caliber

First and most importantly, magazines, like firearms, are designed to handle one type of cartridge (generally). Therefore, Glock mags intended for 9mm can be cross-compatible (more information below) whereas a mag that’s intended to hold, for instance, .40 S&W will not work with 9mm or in a gun chambered for 9mm.

Generally, however, Glock mags of one caliber, within the same generation, are cross-compatible. For instance, G20 magazines, which carry 10mm ammo, are compatible with G29 handguns. Similarly, G17 mags can be used in G19 pistols (but not the other way around, since the G19 mag is too short to seat in the G17).

Within the Same Generation

Generally, Glock magazines of the same caliber, within one generation, will work with other Glock pistols within that same generation.

For instance, two 9mm Gen 1 Glock magazines should be interchangeable, assuming the magazine length was appropriate. It is important to note that if the calibers are not compatible, then the Glock mags won’t be, regardless of generation.

However, Glock pistols, and the magazines they accept, are designed for consistency in geometry and design, even across platforms, helping to ensure cross-compatibility across the generation, assuming the caliber is compatible.

Across Generations

From Generation 1 to 4, most Glock mags are backwards compatible across generations. For instance, a Generation 2 Glock 19 mag should work in a Generation 1 Glock 19.

This is because the features of Glock magazines and handguns within the first four generations were held more or less consistent. For instance, magazines in the first four generations were made with a magazine release notch on the right-hand side.

However, once you get to Generation 5, there’s an exception. Generation 5 Glock mags are generally not backwards compatible with other generations, even of the same model, because the Gen 5 magazines sport raised feed lips and extended base plates, which makes them incompatible with older generation Glock pistols.

Differences Between Different Glock Mag Generations

Let’s take a closer look at some of the distinguishing marks and features of Glock mags by generation, so you can tell what you have:

  • Generation 1 mags: Glock magazines from Generation 1 have a notch on the right side for the magazine release. Gen 1 models also sport a plastic follower and steel spring, but they lack the inner steel lining of newer generations. They’re fairly rare at this point because of their age, but you can tell you’re looking at a Gen 1 mag because they had dimples on the sides of the mag body.
  • Generation 2 mags: Gen 2 magazines sport a notch on the right side for the mag release, as well as an improved feed lip design. Starting with Gen 2, Glock mags were given a full metal lining on the inside of the mag. You can also tell you’re looking at a Gen 2 mag because at the back of the mag body there will be a “2” stamped next to the Glock trademark
  • Generation 3 mags: Glock Gen 3 mags were largely the same as the Gen 2 magazines, except that in Gen 3 we have the first magazines that had magazine extensions.
  • Generation 4 mags: Glock magazines from Generation 4 are backwards cross-compatible with previous generations and are largely the same as Generation 3 mags, with the exception that they are notched on both sides for the magazine release, and also have an additional notch at the front to accommodate ambidextrous magazine releases.
  • Generation 5 mags: Gen 5 Glock mags are notched on both sides for the mag release and have raised feed lips as well as an extended base plate. They also sport a plastic orange follower. They will not interchange with other generations of Glocks, but within the generation, other notes for cross-compatibility apply.

Questions About Glock Mag Compatibility?

It is critically important to use magazines in your Glock pistol that are compatible with it, not only as a matter of safety but to ensure optimal performance and smooth, reliable, jam-free feeding. If you have any questions about compatibility, first check the generation of both the mag and pistol; if you still need information, consult your owner’s manual or get in touch with Glock directly.

Glock magazine

Here for Glock Mags?

The best way to ensure that a given Glock magazine is compatible with your pistol is simply to purchase magazines for that specific model, from the same generation. We carry a wide range of Glock mags here; take a look through our collection and stock up your range bag today.