Updated: Aug 2, 2020
To date, Glock has made 5 generations of pistols. Glock has been the most influential pistols of modern time, designed by Gaston Glock, which started in the early 1980's. I will explain a few of there differences and features of each Glock generation pistols in this post.
First, let me start by saying that Glock only made 4 Generation One models and they were ALL chambered in 9mm. These Gen 1 models are the Glock 17, 17L, 18, and the Holy Grail of them all, the 19.
Generation 1 - Pencil Barrel
Gen 1 pistols have a smooth pebble-grain grip that goes all the way around the grip without any texturing.
Generation 2 - Major Changes
Gen 2 pistols are also 2 pins, except for the larger caliber pistols, they have 3-pins and have no accessory rail. But the Gen 2 pistols do have texturing on the front and back of the grip and they have slightly raised panels on each side of the grip.
The Gen 2 pistols came standard with pre-ban magazines, until September 13, 1994, and they came in a 2 piece "Tupperware" Style box. The Gen 2 pistols went through some major changes during its' manufacturing, to include the following:
They started with a 5 digit serial number, plus the, "US" and went into a 6 digit serial number with the, "US".
They changed from a 90° ejection/breech port in the slide and went to a 15° ejection/breech port.
They went from the two-piece non-captured recoil spring and guide rod tube to a one-piece captured one.
They changed from the old Glock Black parts to new silver-colored parts.
Generation 3 - Finger Grooves
Gen 3 pistols come with molded finger grooves, 3 pins, a small thumb-rest made into the frame and a front accessory rail. There were some early Gen 3 models that some call, "Gen 2.5".
These were made during the transition period going from Gen 2 to Gen 3. For instance, my Gen 3 G34 has 2 pins, finger grooves and an accessory rail. Some have smooth finger grooves and did not come with an accessory rail.
The early Gen 3 models, like My G34, came in a 2 piece Long Slide "Tupperware" style box, but most Gen 3 pistols come in the newer clamshell style box.
Gen 3 RTF2 - Fish Gills - Crescents
These were introduced in 2009. They had the Rough Textured Frame, which was super aggressive, and they had the crescent or fish gill rear slide serrations. These were made in Glock models 17, 19, 21, 22, 22C, 23, 23C, 31, and 32. Some of these models did not have the crescent or fish gills but had the standard straight serrations instead.
Glock eventually stopped making the RTF2 models with the crescent or fish gill serrations and made them with the standard serrations. In early 2011 Glock started making these RTF2 pistols available to Law Enforcement only. Larry Vickers has released a few special edition RTF2 pistols, with the straight serrations, through Lipsey's that were very popular.
I was issued a G22 RTF2 by my department in mid-2009. The grip was so aggressive that I remember going immediately to my LGS and getting a Hogue handball to cover the grip. These came in the newer clamshell boxes.
Gen 4 - Interchangeable Back Straps
Like the Gen 3 pistols, the Gen 4 pistols also came with molded finger grooves, 3 pins, an accessory rail. But they added interchangeable back straps to accommodate different size hands. This was huge because it gave people a choice of back straps to chose depending on the size their hand and they had the option to add a beaver tail.
Glock added a reversible magazine catch/release, new dual recoil spring & guide rods for all models, a new design RTF (Rough Textured Frame) with small pyramids and Glock marked "Gen 4" on the slide. They came in the newer style clamshell boxes.
Gen 5 - No Finger Grooves
Gen 5 pistols went back to the no finger grooves and 2 pins, like the Gen 1 & Gen 2, but they do have the interchangeable back straps, and an accessory rail, reversible enlarged magazines catch Ambidextrous slide stop levers, a Marksman barrel and they are marked, "Gen 5" on the slide. The Gen 5 models have flared mag wells, except for the G26.
The early Gen 5 pistols came with a U shaped cutout at the bottom front of the grip and the frame was not beveled to match the front of the beveled slide. Glock eventually took the U shaped space out and left it solid and they beveled the frame to match the slide. Glock also started putting front serrations on the Gen 5 slides.
The Gen 5 pistols also come in MOS models. The magazines come standard with orange followers and a curved front magazine floor plate. The new Gen 5 models come in the newer clamshell box as well.
This is not by any means an all-inclusive list of the differences between the Glock generations. But it should be enough information to help someone identify the generation of all Glock pistols.
And remember, it does not matter if your Glock model 21 was the first G21 that Glock made. What determines which generation Glock your pistol is, is strictly verified by the attributes recorded in several amazing online articles and printed in very informative Glock reference books. Just because it is the first G21 made, does not mean it is a Gen 1 G21. :)
Glock Junkie has new & used Glock parts, Gens 1-5 Glock Parts, Aftermarket and OEM Glock parts and Glock Pre-ban magazines. Please feel free to check them out at the Glock Junkie store.
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