Glock Numbering System Explained: What Do All Those Numbers Mean?

The Truth Behind Glock Numbering System

If you’ve ever wondered “What does Glock 17 mean?” or “What do the Glock numbers mean?”, you’re not alone. Many firearm enthusiasts find Glock’s numbering system confusing.

The important fact is: Glock pistol numbers (like Glock 17, 19, 18, 26, etc.) do not represent caliber, magazine capacity, or frame size—they are sequential numbers based on Glock’s patent development order.

The Origin of Glock 17’s Name

The Glock 17 was company founder Gaston Glock’s 17th patent, which is why the first Glock pistol was named “17” instead of “1”.

This numbering system continues to this day. Whenever Glock designs a new model, it receives a new number based on patent or design sequence. This means there is no fixed pattern between the numbers.

Common Glock Numbering Myths

Myth 1: Numbers Represent Magazine Capacity

Many people think the “17” in Glock 17 means the magazine holds 17 rounds. This happens to be a coincidence—the Glock 17’s standard magazine indeed holds 17 rounds of 9mm.

But if this logic held true, the Glock 19 should hold 19 rounds, when it actually holds only 15.

Myth 2: Numbers Represent Caliber

Many people mistakenly believe:

  • Glock 45 is a .45 caliber pistol (it’s actually 9mm)
  • Glock 40 is a .40 caliber pistol (it’s actually 10mm)
  • Glock 22 is a .22 caliber pistol (it’s actually .40 S&W)

The actual .22 LR Glock is the Glock 44!

Myth 3: Higher Numbers Mean Newer Guns

Glock’s numbering follows the order designs were started, not the release order. For example, the Glock 20 and 21 began development before the Glock 22 and 23, but the 22 and 23 were released first.

Complete Glock Model Reference Chart

9mm Series

Model Size Category Capacity Features
Glock 17 Full-size 17 rds Original model, military/law enforcement standard
Glock 19 Compact 15 rds Best-selling model, balance of carry and performance
Glock 26 Subcompact 10 rds Concealed carry favorite, “Baby Glock”
Glock 34 Competition 17 rds 5.31" barrel, IPSC/IDPA competition
Glock 17L Long Slide 17 rds 6.02" barrel, precision shooting
Glock 43 Single Stack 6 rds Ultra-slim design, ultimate concealment
Glock 43X Single Stack 10 rds Extended grip G43
Glock 48 Single Stack 10 rds Compact single stack, Slimline series
Glock 19X Crossover 17 rds G17 frame + G19 slide
Glock 45 Crossover 17 rds Gen5 version of G19X

10mm Auto Series

Model Size Category Capacity Features
Glock 20 Full-size 15 rds 10mm standard, woods defense choice
Glock 20SF Full-size 15 rds Short Frame, for smaller hands
Glock 29 Subcompact 10 rds 10mm concealed carry version
Glock 40 Long Slide 15 rds 10mm competition, MOS standard

.40 S&W Series

Model Size Category Capacity Features
Glock 22 Full-size 15 rds Former US law enforcement favorite
Glock 23 Compact 13 rds .40 S&W compact
Glock 27 Subcompact 9 rds .40 S&W concealed carry
Glock 35 Competition 15 rds .40 S&W competition

.45 ACP Series

Model Size Category Capacity Features
Glock 21 Full-size 13 rds .45 ACP standard model
Glock 21SF Full-size 13 rds Short Frame version
Glock 30 Subcompact 10 rds .45 ACP concealed carry
Glock 30S Subcompact 10 rds Slimline slide version
Glock 36 Single Stack 6 rds .45 ACP ultra-slim design
Glock 41 Competition 13 rds .45 ACP competition

.357 SIG Series

Model Size Category Capacity Features
Glock 31 Full-size 15 rds .357 SIG standard model
Glock 32 Compact 13 rds .357 SIG compact
Glock 33 Subcompact 9 rds .357 SIG concealed carry

.45 GAP Series

Model Size Category Capacity Features
Glock 37 Full-size 10 rds .45 GAP standard model
Glock 38 Compact 8 rds .45 GAP compact
Glock 39 Subcompact 6 rds .45 GAP concealed carry

.380 ACP Series

Model Size Category Capacity Features
Glock 25 Compact 15 rds Export market only
Glock 28 Subcompact 10 rds Export market only
Glock 42 Single Stack 6 rds US market .380 ACP

.22 LR Series

Model Size Category Capacity Features
Glock 44 Compact 10 rds Low-cost training option

Special Models

Model Features
Glock 18 Full-auto pistol, military/law enforcement only

Glock Model Suffix Letters Explained

Beyond numerical designations, Glock uses letter suffixes to indicate special versions:

L - Long

Such as Glock 17L, indicating an extended slide and barrel version. The Glock 17L features a 6.02" barrel, much longer than the standard Glock 17’s 4.49" barrel, providing a longer sight radius and higher muzzle velocity.

C - Compensated

Such as Glock 17C, with slots cut in the barrel and slide that allow high-pressure gases to vent upward, reducing muzzle flip. The C version was introduced in 1996.

MOS - Modular Optic System

Such as Glock 19 MOS, with a pre-cut slide for mounting red dot sights. This is the most popular version for modern competitive shooting.

If you’re planning to compete in IPSC Production Optics, the MOS version is the best choice.

X - Crossover

Glock 19X is Glock’s first “crossover” pistol, combining the G17’s full-size frame with the G19’s compact slide. This design originated from the US Army MHS competition.

Glock 43X refers to an extended-grip G43, with a slightly different meaning from the typical X suffix.

SF - Short Frame

Such as Glock 21SF, with the rear grip shortened by 3mm, better suited for shooters with smaller hands. This design eventually became the predecessor to Gen4’s interchangeable backstraps.

S - Slimline

Such as Glock 30S, using a thinner slide design to reduce weight and overall thickness.

MB - Magazine Button

Such as Glock 17MB, featuring an ambidextrous magazine release. Since modern Glocks already have reversible magazine releases, this design is no longer produced.

Glock Generation Evolution

Glock has not only model numbers but also “Generations”:

Gen 1 (First Generation)

  • 1982-1988
  • Only Glock 17 existed
  • Smooth grip, no finger grooves

Gen 2 (Second Generation)

  • 1988-1998
  • Added front and rear grip texturing
  • Added serial number plate
  • Introduced more calibers and sizes

Gen 3 (Third Generation)

  • 1998-2010
  • Added finger grooves
  • Added thumb rest
  • Introduced accessory rail

Gen 4 (Fourth Generation)

  • 2010-2017
  • Reduced grip size
  • Interchangeable backstraps
  • More aggressive texturing
  • Reversible magazine release
  • Dual recoil spring assembly

Gen 5 (Fifth Generation)

  • 2017 to present
  • Removed finger grooves
  • Flared magwell
  • Ambidextrous slide stop
  • Glock Marksman Barrel (GMB)
  • nDLC finish

V Series - 2025 Latest

  • Released December 2025
  • Anti-conversion features
  • Redesigned slide cover plate
  • Prevents illegal full-auto conversion

Glock Size Classification System

Beyond numerical designations, Glock has a size classification system:

Category Representative Models Use Case
Standard G17, G22, G31 General purpose, range
Compact G19, G23, G32 Everyday carry, duty
Subcompact G26, G27, G33 Concealed carry
Competition G34, G35, G41 IPSC/IDPA competition
Long Slide G17L, G40 Precision shooting, hunting
Crossover G19X, G45 Multi-purpose
Slimline G43, G43X, G48 Ultimate concealment

How to Choose the Right Glock Model?

Competitive Shooting

Everyday Carry

  • Medium build: Glock 19 (best-selling compact)
  • Ultimate concealment: Glock 43, Glock 43X
  • Larger hands: Glock 48

Home Defense

  • Standard choice: Glock 17, Glock 19
  • Large caliber preference: Glock 21 (.45 ACP)

Outdoor Use

  • Wildlife defense: Glock 20 (10mm)
  • Hunting backup: Glock 40 MOS

Airsoft Glock Training

No matter which airsoft Glock model you choose, you can use AirsoftShotTimer for effective training.

Summary

Glock’s numbering system may seem complex, but just remember one core concept: the numbers are patent sequence, not specifications.

To quickly identify Glock models, remember these principles:

  1. The number only tells you “this is Glock’s nth design”
  2. To know caliber and size, consult the reference chart
  3. Letter suffixes indicate special version features
  4. Gen represents the technological generation

We hope this complete analysis helps you better understand the Glock pistol family!

Further Reading