If you’ve ever consulted a Glock catalog, you may have come across terms like Compact, Slimline, Competition, or Subcompact. All of these words refer to the pistol’s frame size. Yet, they may describe very similar models, to the point it can be challenging to understand the differences.
Learn about all the differences between the different Glock frame sizes and how to choose the correct frame size for your needs.
What are Frame Sizes?
If you’re unfamiliar with the concept, you first need to understand that Glock categorizes its products under specific criteria to help customers distinguish between their products.
One of these criteria is frame size. The size of the pistol’s frame influences all other aspects of the gun: barrel and slide length, frame and slide thickness, and to an extent, chambering and magazine compatibility.
Although Glock was not the first manufacturer to create compact versions of their standard pistols (the Walther PPK may have been the first, predating Glock by over 55 years), they have arguably popularized the practice, giving rise to terms such as subcompact.
Guide to Glock Frame Sizes
Officially, Glock recognizes five frame sizes in its model lineup: Standard, Compact, Subcompact, Slimline, and Competition.
The Standard Glock frame size comprises full-size models patterned after the original Glock pistol, the Glock 17.
The current Standard models are as follows:
- Glock 17 (9x19mm)
- Glock 20 (10x25mm Auto)
- Glock 21 (.45 ACP)
- Glock 22 (.40 S&W)
- Glock 31 (.357 SIG)
- Glock 37 (.45 GAP)
Although all of these pistols feature nearly identical dimensions, Glock enthusiasts sometimes unofficially distinguish between “Small-frame” and “Large-frame” models.
The difference between a small-frame and a large-frame pistol is interchangeability. Small-frame models feature fully interchangeable slide assemblies with any other small-frame model, and the same is true of large-frame models.
However, you cannot install a large-frame slide assembly on a small frame (and vice-versa).
For example, this interchangeability allows the end-user to convert a Glock 17 to a Glock 22 merely by removing the G17’s slide assembly and magazine, installing a G22 slide assembly, and inserting a .40-caliber magazine.
The Compact Glock frame size comprises models either patterned after or resembling the original compact Glock, the Glock 19.
Current Compact Glocks comprise the following models:
- Glock 19, Glock 19X, Glock 45 (9x19mm)
- Glock 23 (.40 S&W)
- Glock 32 (.357 SIG)
- Glock 38 (.45 GAP)
- Glock 44 (.22 LR)
Enthusiasts further separate Compact Glocks into three sub-categories: original compacts, crossover models, and rimfire models.
The G19, G23, G32, and G38 comprise the original compacts, as they are all based on the original Glock 19, a reduced-size version of the Glock 17. Like Standard small-frame models, they also feature interchangeable slide assemblies, enabling conversions from one model to another.
The Glock 44 is the sole rimfire compact, and so far, the only rimfire Glock pistol ever made. It possesses very little in common with most other Glock pistols, employing a direct blowback mechanism instead of the centerfire models’ tilting-barrel, short-recoil operation.
The G19X and G45 are classified in the Compact category but are better known as crossover pistols. These similar pistols are based on the prototype Glock 19 MHS, featuring a G19-sized frame and slide length, but with the grip length (and overall height) of a G17.
The Subcompact lineup comprises pistols modeled after the original subcompact Glock, the Glock 26.
Glock created the Subcompact frame size to answer the G19’s perceived shortcomings as a concealment pistol (mainly, overall size and bulk). The primary purpose of these pistols is deep-concealed carrying, and law enforcement officers use them as backup guns.
Glock classifies the following models as Subcompacts:
- Glock 26 (9x19mm)Glock 27 (.40 S&W)Glock 29 (10x25mm Auto)Glock 30 (.45 ACP)Glock 33 (.357 SIG)Glock 39 (.45 GAP)
Like the Standard models, the G29 and G30 are large-frame subcompacts, whereas others are small-frame, with the same interchangeability factor.
The Slimline lineup comprises a selection of pistols visually similar to Compacts and Subcompacts, featuring slim frames and slides intended to facilitate concealed carrying and reduce printing.
These pistols often feature single-stack magazines incompatible with any other frame sizes, even if they are of the same caliber.
Although Glock categorizes them as Compacts and Subcompacts, Slimline frames are sufficiently distinctive to merit their own category here.
The current Slimline models are as follows:
- Glock 36 (.45 ACP)Glock 42 (.380 ACP)Glock 43, Glock 43X, Glock 48 (9x19mm)
Although not marketed as such at the time, the Glock 36 is the first true Slimline Glock. Introduced in 2000, the G36 is essentially a Glock 30 with a slimmer frame and a single-stack 6-round magazine.
The Glock 42 was introduced in 2014, following the same principle as the G36 (single-stack, 6-round magazine) but in the much smaller .380 cartridge. The Glock 43 followed suit in 2015, being essentially a 9x19mm version of the G42.
In contrast, the Glock 43X and Glock 48 are crossover models.
The Glock 43X is essentially a Glock 43 with a lengthened grip and a matching 10-round magazine, possessing the overall height of a Glock 19 but almost 0.25” thinner.
The Glock 48 is a further development, using identical frame dimensions as the G43X but mating it to a 4.17” barrel and matching slide.
Competition Glocks feature Standard-size frames with elongated slide assemblies and barrels designed to maximize accuracy. They are ideal for target and competition shooting.
The current Competition Glock pistol lineup is as follows:
- Glock 34 (9x19mm)Glock 35 (.40 S&W)Glock 41 (.45 ACP)
Functionally, these pistols are identical to their Standard counterparts other than barrel length: 5.31”, instead of the standard models’ 4.49” (small-frame) or 4.61” (large-frame).
The similarities include magazine compatibility and interchangeability. For instance, the G41 is a .45 ACP pistol and is large-frame, whereas the others are small-frame.
Although Glock officially considers it part of its Long Slide model lineup, the Glock 17L is the only member of that group, leading Glock fans to lump it in with the Competition models.
The G17L is nearly identical to the G34 but features an even longer 6” barrel.
Which Frame Size Should I Use?
The right frame size depends mainly on your intended application.
- If you want a general-purpose personal protection handgun that you can shoot comfortably and carry either openly or concealed, you may enjoy the Compact pistols.
- If you need concealment above all, choose one of the Subcompact or Slimline pistols.
- If you need a full-size handgun for duty use or open carrying (check your local laws), go with one of the Standard models.
- Lastly, if you want a reliable competition handgun with a long barrel and sight radius right out of the box, you can’t go wrong with a Competition Glock.
Become a Glock Expert
Although Glock pistols seem very similar at first glance, as long as you know your pistol’s intended purposes, selecting a suitable frame size for the job does not have to be challenging.
Don’t hesitate to visit a local gun shop or firearm retailer to see the pistols in person and get a feel for them.
If your local store has a range and allows customers to try out their inventory, you should take advantage of it. After all, the best way to decide if a pistol is right for you is to shoot it.