Umarex Glock 17 Gen4 Part 1

Umarex Glock 17 Gen4 Part 1

From zero to three in a year

By Dennis Adler

Glock broke from its tradition of only building medium (9mm) to large (.45 APC) caliber handguns in two ways, first with the introduction of a .380 ACP in 2013 (the Glock 42), and then in what I see as a significant departure from the past, working in concert with Umarex to develop and introduce three CO2 models between summer 2018 and summer 2019, the non-blowback Model 19 Compact (far right), the blowback action (with self contained CO2 BB magazine) Third Generation Glock 17 in the late fall of 2018 (center), and now in summer of 2019 the high end, blowback action Glock 17 Gen4 with interchangeable backstrap panels, self-contained CO2 BB magazine, and field stripping capability for total authenticity. The price spread, (average selling price, not MSRP, rounded off to the next dollar), ranges from $70 to $100 to $130 for the Gen4. The two Glock 17 models, and to a lesser extent the Glock 19, are all suitable as training guns for learning how to handle and shoot a Glock pistol.

This time last year we were moving on from what seemed a disappointment, the Umarex Glock 19, which had arrived in June appearing to be a stunningly authentic Glock Compact model, but unfortunately powered by a CO2 cartridge in the grip and using an old style stick magazine. Displayed in a blister pack, it was an entry level gun commensurately priced for sale in big box stores. And there was one collective groan within the adult airgun community. But, there was also the realization that Umarex and Glock were not looking at one gun when they developed the G19 CO2 model. An air pistol bearing the Glock name was an honest to goodness epiphany for Glock, a company that had held so steadfastly to its ways since the 1980s that Glock never even ventured into offering a factory-built model in .22 LR! Then, all of a sudden they allied with Umarex and broke the entry level CO2 barrier with a non-blowback action air pistol. The realization was that Glock needed to follow companies like Sig Sauer that were developing and introducing CO2 models that could be used as training guns, as well as become part of an ever expanding global air pistol market in Europe and the United States.

It was a form of Glock Perfection; the CO2 model Glock 19 was the company’s first .177 caliber model (there had been Airsoft versions previously) and the G19 looks exactly like a 9×19 Glock pistol in every detail right down to the finish on the slide. The non-blowback action model took the basic entry-level air pistol to a new standard of quality, fit and finish in 2018.
When I tested the Glock 19 CO2 model in June of 2018, I absolutely loved the idea that my centerfire pistol Glock GTL 22 tactical light and red laser fit perfectly on the CO2 model’s dustcover rail. Even as a non-blowback action BB pistol, this really made it a great training and practice gun that could provide live fire feedback downrange for pennies compared to even the most affordable 9mm FMJ training rounds. The attention to detail in Glock’s first CO2 model was very impressive; there was nothing cheap about this air pistol except the price.

Having worked on Glock Autopistols magazine for years and having come to realize how conservative the company was, leaving every imaginative idea that wasn’t pure form follows function Glock ideology to the aftermarket (and that is a big market), I was amazed at the arrangement between Umarex (which is also Carl Walther), Gaston Glock, and his Austrian arms making company. But why a non-blowback action model with a stick magazine? That was the question I had to answer last June for Airgun Experience readers. The answer, like it or not, was a slow, well thought out, insinuation of the Glock brand across the entire air pistol marketplace from entry level to the now forthcoming Glock 17 Gen4 model, which completes what is likely to be the first of several product cycles over the coming years.

Hard to tell from the outside, the first Glock CO2 model didn’t look like an air pistol from the exterior. Impressive as it was, to many it was also a disappointment because the long anticipated Umarex Glock used a removable backstrap (like the Umarex Walther PPS) to load the CO2, and an 18-shot stick magazine with a convincing Glock base pad. While this gun left some of us wondering what was going on, the facts were that Glock was building its CO2 line from the bottom up beginning with a non-blowback action entry level pistol, intended for mass market sales rack display and an affordable average selling price of under $70. Why not go with the big gun first? You have to think like Glock. They were about to slowly insinuate themselves into a market they had never been in. Step two was just six months distant.

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If you look at Glock evolution over the past 37 years you can see that the company makes changes to its products in very well orchestrated ways, from the original Glock 17 c.1982, which was a groundbreaking design with as few features as possible and intended to be a one-size-fits all, 9mm military issue sidearm (Austrian military, Austrian police), to the improved Glock 17 in 1989, (essentially the second generation, but not officially), the addition of the Compact Glock 19 and other sized models, plus expanding into a variety of calibers from .45 ACP to .380 (the latter in 2013), further ergonomic and internal improvements with the third generation (1998), and finally, significant design evolution with the Gen4 in 2010, which brings the company up to the present day with the addition of new Gen5 models in 2017.

Comparing the centerfire models, the Gen4 Glock 17 (right) illustrates several significant differences from the previous Third Generation model, including the new grip design and tactile surface derived from Glock’s earlier RTF2 models, and slightly smaller standard backstrap, part of the Gen4 design allowing for addition of replaceable backstrap panels. This was an innovation for Glock, even though other gunmakers had already gone to replaceable backstraps long before Glock decided to redesign their polymer frame.

Glock has always gone from strength to strength, only making improvements for the sake of building a better gun or meeting a broad consumer or contract military/law enforcement requirement (like the Third Model, for example, with a dustcover accessory rail), and not for the sake of making new products. Can we say that this same strategy has been applied to the CO2 models? From my experience with the company (and Umarex, as well), I would have to say yes. Glock started filling the CO2 niche from the bottom up. People who were interested in a Glock air pistol were drawn to the G19, even more experienced air gunners who had expected more, were nevertheless attracted to how extraordinarily well-built the non-blowback action model was. I was even amazed at the attention to detail in individual parts, that on this specific gun were non functional. The fit and finish were impressive, and above all else, the clear message was sent that this Glock CO2 pistol and all further models would not be burdened with telltale white lettering and safety warnings, and that the construction of the frame and slide would be as close to the actual centerfire pistol as possible, a visual 1:1 air pistol variation. And all this effort had gone into a CO2 model that sells for less than $70 (MSRP is $79.95). The expectations for what would come next were astounding.

With the addition of the Umarex Glock 17 at the end of 2018, the adult airgun market had already had its appetite whetted by the entry-level gun that summer, and expectations were very high for the next model. Matching the Third Model Glock 17 inch for inch, the CO2 model had all the correct Glock factory markings and a slide that locked back on an empty magazine. It also surprised with an impressive average velocity of nearly 380 fps.

By the end of 2018, the G17 Third Generation model had became the basis for the second Glock CO2 pistol, and this gun checked all the boxes but one. Based on the still in production, lower-priced Third Generation Glock 17, the new CO2 model gave us a self-contained CO2 BB magazine, 1:1 dimensions to the centerfire model, (including fitting the highly popular Blackhawk Serpa Level II holster), and delivering higher velocity for a BB model than any other blowback action CO2 model on the market, an average of 376 fps. This new Glock 17 air pistol was suitable for both 7 and 10 yard training exercises, almost impossible with most blowback action air pistols sending BBs downrange at 300 to 320 fps. The one flaw, and the one thing that kept it from being 2018’s Replica Air Pistol of the Year, was its inability to be field stripped, one of the basic requirements for winning the title. The firing system in the Glock Third Generation-based CO2 model sacrificed disassembly for velocity, but the gun was a winner even without the title. With a MSRP of 109.99 the new Glock, still enclosed in an injection molded blister pack, was selling for an average of $99.99, only $20 more than the non-blowback G19 model. Both models had come out in 2018, just six months apart, though supplies of the Third Generation model were not in the distribution pipeline until earlier this year. By then the rumor that a Gen4 was in the works were circulating as the Third Generation G17 CO2 model was just hitting the shelves. Even so, Glock had introduced both models in the same year. For Glock, this was moving at the speed of light with each new gun filling a different price point and delivering more features than the previous model. It was Glock marketing compressed from years into months.

Once again, the Glock GTL was used to compare fit with the new blowback action Glock 17 last fall, when I reviewed the second Umarex Glock model of the year for Airgun Experience. The G17 CO2 model’s ability to use Glock accessories, like the GTL, as well as fit in Glock holsters, made this model a perfect understudy to the 9mm pistol.

Before delving into the new Umarex Glock 17 Gen4, to better understand what this new CO2 model brings to the blowback action air pistol table, I am going to use part of my Glock Autopistols review of the 9mm model to set the stage for what has been duplicated with the air pistol, which we will pick up in Part 2.


The cornerstone of Glock engineering for more than three decades has been the Safe Action trigger design introduced with the original Glock 17. Utilizing a toggle safety projecting through the face of the trigger, the gun is always in a safe condition unless the trigger is pulled, very much the same concept as a revolver where the trigger is the only actual safety. The difference with the Glock is that when the Safe Action system is activated, internal safety devices make the gun inoperable so it cannot accidentally discharge if dropped. This is accomplished through three separate safety mechanisms activated the instant the trigger is released.

The Gen4 looks remarkably similar to its predecessor but is a very different gun. Among the exterior differences are the new front grip strap serrations, squared magazine well frame contour, and larger guide rod opening under the muzzle. (All of these features are reproduced on the latest CO2 models.)

With the Gen4, Glock finally addressed the biggest complaint; grip size. While not a big gun, the Glock was not sized for everyone as the company had originally thought. In the interim years more women entered the military and law enforcement fields, and not everyone wearing a uniform or a badge, man or woman, was tall and had medium to large-sized hands. The gun had been built around a standard that had changed since the 1980s. The Gen4, first with the Glock 22 and then Glock 17, were the first new models to offer interchangeable backstrap panels to accommodate a greater variety of hand sizes. The standard grip, which is now slightly smaller than the previous model’s, can be covered over by one of two different panels, medium and large, that attach at the base of the grip frame and lock into position with an extended trigger housing pin passing through openings in the grip panel and frame.

A head-to-head visual comparison of a Third Model Glock 17 (top) and the Umarex Glock G17 CO2 model illustrates the fine attention Umarex and Glock gave to making a CO2 blowback action pistol that is fully representative of the centerfire model. The CO2 models do not bear a caliber stamping on the left side of the slide. Glock’s one easy professional tell.

While the aesthetics of the Gen4 certainly improve the gun’s serviceability, the armsmaker added one more change, a new recoil system. The original Glock 17 and all subsequent variations had one inherent problem; being lighter weight polymer framed guns, they were prone to more aggressive recoil, even in 9mm. Glock had addressed this in various ways over the years with longer barrels (original Glock 17L) and competition models (initially with the Glock 17C), but the fundamental issues remained.

The Gen4 also revised the recoil system for the 9mm pistols. What will the recoil system be for the CO2 model? We’ll find out as we get further into the new Gen4 version.

The Gen4 takes a fresh approach utilizing a double recoil spring and guide rod. The primary recoil spring goes over the guide rod as before, only this is a heavier, more tightly wound round spring, as opposed to the flat spring that preceded it. This assembly is then shrouded by an alloy case around which is wound an even larger secondary recoil spring. The combination, though a bit more demanding when cycling the slide to chamber the first round or clear the gun, significantly reduces muzzle flip, providing the ability to reacquire the sights for faster follow-up shots. In comparison to the previous Glock 17, firing the Gen4 feels closer to that of a .38 Special than a 9x19mm. The Gen4 line includes the Glock 17 and 19 (9×19); 22 and 23 (.40 S&W); 26 Subcompact (9×19), 27 Subcompact (.40 S&W), and Standard size 31 (.357), 34 (9×19), 35 (.40), and 37 (.45 G.A.P.).  [Editor’s note: These versions were current at the time of the original Glock Autopistols article in 2012 and are not updated to 2019 models and calibers].

Considering the number of Glock 17 Gen4 models in use today for law enforcement, as well as for civilian use as a personal protection gun, a 1:1 CO2 model for basic training skills, from safe holstering, reloading, trigger control, and proper aiming techniques, is duplicated without the cost of expensive ammunition, or even wear on a centerfire model. It is one of the most affordable ways to learn gun handling skills that translate to a centerfire counterpart. This is especially so for Glock models, as all guns, regardless of caliber or frame size, operate the same way. The gun at the top is a centerfire Glock 17 Gen4, the gun at the bottom is the new CO2 model. Need I say more?

Almost 40 years after the original 9x19mm Glock 17 was introduced, there are now Glock models in virtually every caliber and frame size from 9mm subcompacts to hefty 13+1 round .45 autos, and even a .380 pocket pistol. The Gen4 series represents better-handling, better-engineering and more versatility; the differences, although subtle, are both distinctive in appearance and in function. It’s a 21st Century Glock.

Beginning in Part 2 we will see how much of the 9x19mm Glock 17 Gen4 has been carried over into the new Glock CO2 model’s design and handling. 

A word about safety

Blowback action airguns provide the look, feel and operation of their cartridge-firing counterparts and this is one reason why they have become so popular. Airguns in general all look like guns, blowback action models more so, and it is important to remember that the vast majority of people can’t tell an airgun from a cartridge gun. Never brandish an airgun in public. Always, and I can never stress this enough, always treat an airgun as you would a cartridge gun. The same manual of operation and safety should always apply.

2 thoughts on “Umarex Glock 17 Gen4 Part 1”

  1. I see they are including the extra backstraps with the C02 model, just like the real deal. Does that include the one with the beavertail? I had a GEN4 and now on a GEN5 and I really like that backstrap. If it isn’t included, would my GEN5 backstraps work? Also is the mag the same as the GEN3 pistol? I would think for logistical purposes they would want to use the same mag.

    • The CO2 model comes with two of the standard backstraps not the extended beavertail. I am not 100 percent sure the centerfire model’s backstraps will work, so I am going to get one of the beavertail backstraps and try it. Stay tuned for that. As to the magazines being the same, I’m going to answer that in Part 2 on Thursday…Spoiler alert, you’re not going to like the answer…


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