The Glock 19 has consistently been one of the most popular pistols in America. The Glock 17 hasn’t been far behind. The Glock 22 and Glock 23 were the most popular pistols in American law enforcement for a couple of decades, and millions of other Glock models have sold in the United States in the last forty years. The U.S. market has plenty of Glocks to choose from in a variety of sizes and calibers…and Generations.

During this time a lot of changes have been made to the Glock pistol. The Glock pistol has seen a slow evolution following its initial revolution in the firearms industry. It has evolved through several Gens, each featuring slight changes which may or may not be “improvements,” depending on the eye of the beholder. Knowing what Generation your Glock can be important when buying a Glock or accessories for it.

Let’s take a look at the various generations (or “Gens”) of Glock pistols.

Gen 1 Glock

The Gen1 Glocks are Gaston Glock's 17th design and the original Glock pistols on the market. These were the guns that completely changed ideas about handguns among military, civilians, and law enforcement alike. Aside from their polymer frame, the 17-round capacity of the original Glock 17 was incredible. The guns also included polygonal rifling which was very novel at the time. Glocks immediately became known for being simple, and a Glock Armorer (rather than a gunsmith) could fix most problems at the using-unit level.

The Gen1 Glocks were produced during a fairly short time frame (as compared to other Glock Gens), and in only two models. These Glocks are rare due to (relatively) low production numbers, many being owned by collectors, and many having reached their functional lifespan. Let’s take a look at some features of the Gen1 Glock, and how to tell them from different generations.

Production Span: 1982-1988

Calibers: 9mm Luger

Models: 17, 18, 19

Notable Features: The Gen1 Glocks are most notable for their unique grip. The grip lacks finger grooves and has very mild texture all the way around. The grip also lacks the thumb rest that would show up on Gen3 Glocks. The front of the magazine well also features a half-moon cutout to aid in releasing magazines. The dust cover is smooth and lacks an accessory rail. These Glocks were so early and the design was still being refined, some features on these guns may vary slightly.

Gen 2 Glock

The Gen2 Glocks saw changes in the grip, as well as the addition of several new models, and additional calibers other than 9mm Luger. By the time this Gen came along, Glocks were extremely popular among police, competitive shooters, and citizens interested self-defense. They were known to be accurate, reliable, and available at an affordable price. There are still quite a few of these Glocks on the used market as they were produced for almost a decade, and in huge numbers.

Production Span: 1988 – 1997

Calibers: .380 ACP, 9mm Luger, 9x21mm, .357 Sig, .40 S&W, 10mm Auto, .45 ACP

Models: 17 - 33

Notable Features: The most obvious features of the Gen2 Glocks is again, the grip. The Glock Gen2 guns have the “grenade grip” lacking finger grooves, but with coarse checkering front and rear. The magazine These Glocks still lack the finger ledge, but have more clearly-defined side grip “panels.” The dust cover also lacks the accessory rail that showed up in Gen3.

Note on .380 ACP Gen2 Glocks: The Glock 25 was never sold on the U.S. market due to import regulations

Gen 3 Glock

The third generation of Glock pistols is still in production today, over 25 years later. These Glocks are very prolific with both new and used models for sale nearly everywhere. The Gen3 Glock pistols seem like the "standard Glock" compared to the more feature rich, newer generations. Combined, the Gen3 Glocks represent a huge percentage of the pistols in the United States. If you have a Glock pistol and wonder what generation it is, there’s a good chance it’s a Gen3. The Gen3 Glock has been made in every caliber that Glock makes, and nearly ever model, excluding some of the Slimline pistols, and a couple other oddballs, discussed at the end.

Production Span: 1997 – Present

Models: 17 - 39

Calibers: .380 ACP, 9mm Luger, 9x21mm, .357 Sig, .40 S&W, 10mm Auto, .45 GAP, .45 ACP

Notable Features: The Gen3 Glock handguns, once again, have a very distinctive grip profile. The Gen3 Glocks have finger grooves, which are hotly contested. They also introduce the “thumb rest” high on the grip panels, as well as the accessory rail that is now standard on Glock pistols.

Gen 4 Glock

The Glock Gen4 pistols were the first Glock handguns to have a “Gen” clearly marked on the slide, and some purists argue that this is the first “true” generation of Glocks after the original. The Gen4 is very common, and is the latest generation in many models and calibers, the Gen5 guns being somewhat limited.

Production Span: 2010 – Present

Models: 17 – 41

Calibers: .380 ACP, 9mm Luger, 9x21mm, .357 Sig, .40 S&W, 10mm Auto, .45 GAP, .45 ACP

Notable Features: Once again, the biggest update to the Gen4 Glock is the grip. In this case the finger grooves and thumb rests are still there, but the grip has interchangeable backstraps. This was a fairly radical move for Glock at the time. The Gen4 pistols also have a reversible magazine release button. And once again, the “Gen4” stamp on the slide leaves little room for interpretation about what generation these pistols fall into.

Gen 5 Glock

The Gen5 Glocks are a huge leap forward with a significant number of design changes.

Production Span: 2017 – Present

Models: 17, 19, 19X, 22, 23, 26, 27, 34, 35, 42, 43X, 44, 45, 48

Calibers: .22 LR, .380 ACP, 9x19, .40 S&W

Notable Features: The Gen5 Glocks, like the Gen4s, are marked with their generation on the left side of the slide. These pistols once again drop the finger grooves, and have the interchangeable backstraps introduced in Gen4. They also have fully ambidextrous controls including an ambidextrous slide stop lever and reversible magazine release button. The Gen5 Glocks also have a flared magazine well, and a new barrel designed the Glock Marksman Barrel (GMB).

Slimline Glocks

Some Glocks fall into what Glock refers to as the “Slimline” series. These are single stack pistols with a very slim grip, and several models including the Glock 43 and 48 have become immensely popular. most of them align closely with the Gen5 guns, having the Glock Marksman barrel, lacking finger grooves, and having ambidextrous controls.

Production Span: Varies by model

Models: 36, 42, 43, 43x, 48, 43xMOS, 48MOS

Calibers: .380 ACP, 9mm Luger, .45 ACP

Notable Features: These guns vary in generational features with the G36 having Gen3 features and all others being more closely aligned with Gen5. The most important feature of these guns is their single-stack magazine and very slim grip.

Glock Gen’s: The Outliers

There are a few “subgenres” of the Glock platform. Some of these are already listed in other Generations, but also fall into their own generation, some according to Glock’s official nomenclature, and others according to popular convention. Let’s take a look at these pistols.

Gen “2.5” Glocks: There are a small number of pistols out there that are considered "transitional models," between Gen2 and Gen3. These feature the finger grooves of Gen3, but lacking the accessory rail, like a Gen2, a notable difference.

RTF Glocks: Some Gen3 Glocks were manufactured with a “Rough Texture Frame,” characterized by two notable differences. First, the grip panel has sharp, raised pyramids that textured the surface. Second, these guns also had rather unique, boomerang-shaped, “fish gill” slide serrations. These guns were produced in very small numbers and are highly desirable.

MOS Glocks: Some newer generation Glocks bear the additional label of “MOS,” as in “Glock 48 MOS”. In most Glock MOS models this means that the slide is cut for the installation of a red dot optic. For the Glock models 43X and 48, the MOS version is also the only version upon which an accessory rail is available.

Crossover Glocks: Glock also has a line of newer generation pistols referred to as “Crossover” models. These including the 19x, 43x, 45, and 45x. These are called Crossover pistols because they typically feature the frame of one existing model on the slide of another. The Glock 19X, for instance, features a Glock 19 slide on a Glock 17 frame. These guns also generally align with the Gen5 Glocks, having the Glock Marksman barrel, and an ambidextrous magazine release button and slide stop lever.

Functional Differences

After having read all of this you may be wondering, “why does this matter? Why do I need to know what Gen my Glock is?”

Sometimes there are functional differences that have real application for law enforcement officers or concealed carry. One instance is when purchasing aftermarket parts like trigger kits. Due to some internal differences between certain Glock generations, it is important to know what Gen your Glock is before buying a drop-in trigger. What works on a Gen5 may not work on a Gen2 or Gen3.

The generation you choose may also influence usability to some extent. If you have large hands and desire the interchangeable backstraps, you certainly need to pay attention when you purchase a new Glock. You also need to pay attention if you wish to have an accessory rail – an important feature if mounting a light or laser is important to you.

It is important to pay attention to small nuances in the model nomenclature. Thinking that, “a Glock is a Glock” and missing this subtlety. This is very important to pay attention to if you wish to use your Glock with an optic.

Upgrade Your Glock with Overwatch Precision

Regardless of what Generation your Glock is, Overwatch Precision can help you upgrade it. Despite the pursuit of Perfection, many Glock users desire an upgraded trigger. We offer our TAC triggers and DAT triggers – and plenty of other upgrades – for every Glock Generation, from Gen1 to Gen5...all you need to know is your Glock pistol's generation and model number!