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CO2 First Look at the Umarex Glock G17 Blowback Action Model

First Look at the Umarex Glock G17 Blowback Action Model

A first look at the long awaited CO2 Pistol

I have said this before but it is worth repeating, a good air pistol doesn’t have to be a training gun but a CO2 training gun has to be a good air pistol. The Umarex Glock G17 qualifies as both. One of the most important features a training gun must have is correct dimensions so that it can interchange with holsters, magazine pouches, and primary accessories used with its centerfire counterpart. Even if you are not looking for a training gun, have no intention of ever owning a centerfire G17, it should at least fit in a G17 holster.

Making it realistic means making it the right size in every detail and the new Umarex Glock G17 is dimensionally exact to the centerfire Third Model (top) and it fits into all Glock holsters as cleanly as the 9x19mm pistols.

When the Umarex Glock G19 came out earlier this year it failed that requirement by being a fraction oversized through the triggerguard which prevented it from fitting into or locking in any G19 level 1 or higher injection molded holsters. It fit tightly into an ASG Strike Systems injection molded Level 1 tactical holster made for a basic size gun, and it fit into almost every leather holster I tried. Leather gives, injection molded holsters don’t.

The Blackhawk Serpa Level 2 locking holster, which can be configured as a belt rig (shown) or with the included paddle, switched to an easily mounted and removed paddle holster. The Level 2 injection molded Serpa locks the G17 in place through the triggerguard and the pistol can only be removed from the holster by depressing the release with the trigger finger when drawing the gun. This also properly aligns the trigger finger with the side of the frame as the gun is drawn.

The first thing I did after unpacking the G17 was pick up the gold standard of Glock 17 and Glock 19 holsters, the Blackhawk Serpa Concealment Holster. If the Umarex model fits the Blackhawk it will fit all law enforcement and civilian Glock 17 rigs. And it fits the Serpa like a G17. This is the first test for the new CO2 model and it passes.

How exact is the Umarex Glock G17 to the centerfire 9x19mm pistol? By the numbers 1 through 7, here are the centerfire pistol’s specs: 8.03 inches, 7.32 inches, 1.26 inches, 1.0 inches, 5.47 inches, 6.50 inches, and 2.83 inches.

If the holster fits…

Since the Umarex Glock G17 fits the Blackhawk Serpa Level 2 triggerguard locking holster for the centerfire pistol, the CO2 model should have the exact same dimensions as the 9x19mm. This is the second test, not that it makes the gun better, but it shows that Glock and Umarex went the extra distance to get this blowback action model right. I gave you the specs on the centerfire model in Part 1 so here is how the CO2 model stacks up visually, and with a tape measure.

The CO2 version measures 8.03 inches, 7.32 inches, 1.20 inches, 1.0 inches, 5.47 inches, 6.50 inches, and 2.83 inches. Almost a perfect match.
  • Specifications: Glock G17 Third Model/Umarex Glock G17 Third Model
  • Caliber: 9x19mm/.177
  • Overall length: 8.03 inches/8.03 inches
  • Barrel Length: 4.49 inches/4.49 (internal length 4.25) inches
  • Height: 5.47 inches/5.47 inches
  • Width: Slide 1.0 inches/1.0 inches
  • Action: Semi-Auto/Semi-Auto
  • Safety system: Safe Action/manual safety
  • Capacity: 17/18
  • Weight: 24.87 oz/27.0 oz (with empty magazine)
Nothing is lost in the details with matching grip panel stippling, finger grooves and front and backstrap checkering. Although the CO2 model (bottom) does not have any shell cases to eject, the ejector is duplicated as a slotted in piece at the back of the slide’s ejection port. On the centerfire pistol the square projection at the front also functions as a loaded chamber indicator by protruding slightly out from the side when a round is chambered. Slide markings are nearly identical and there are no white letter safety, warning, or manufacturer’s markings to detract from the clean lines of the Tenifer-type slide finish.

What does this reveal? The one tiny flaw in the design, the manual safety, which is basically a mandatory item for an air pistol (and there’s lot’s of grey areas in this as we know, but Umarex and Glock went by the book). The manual safety is hidden under the dustcover in the frame recess occupied by the serial number plate on centerfire pistols. It is a simple sliding safety that you can leave set to fire and forget about. But, since Umarex did not use a functional Glock Safe Action trigger, if you were to try and pull the trigger from the side without engaging the blade safety the CO2 model will still fire, whereas a centerfire pistol will not discharge the pistol unless the blade moves back in unison with the trigger. This is not so much a training issue as it is an air pistol safety issue. Why have two safeties and increase the cost of manufacturing if the gun has to have a manual safety fitted anyway? The blade safety on the CO2 model does pivot like an actual Safe Action design and pulls with the trigger, so when you look at it that way, you really can’t fault Umarex or Glock for eliminating a working Safe Action trigger.

Shorter recoil vs. short recoil is shown in this comparison of the Umarex Glock G17 and Umarex S&W M&P40 models. The M&P40 (bottom) uses a version of the J.M. Browning short-recoil, locked-breech design and the slide comes all the way back exposing the interior of the frame. Aside from the CO2 nozzle, the interior of the M&P is not obstructed, and like a centerfire gun you can see down though the grip with the magazine removed. This design facilitates the most accurate operation and allows field stripping to provide a total training experience with a CO2 pistol. The Umarex Glock 17 uses a shorter recoil system and the slide does not come back as far. This is evidenced by the back third of the barrel lug still showing, and the magazine locking mechanism extending to the back of the barrel.

Short Blowback and Shorter Blowback

There are two basic types of blowback action designs used for CO2 pistols, a very close approximation of the John M. Browning short-recoil, locked-breech design with a tilting barrel and fully functioning barrel lug and slide ejection port interface, and the less exact, shorter recoil design where the slide does not move as far back as it does on a centerfire pistol or a CO2 pistol using the full Browning design. I pointed this out in Part 1 regarding the locked back slide and what you can see when you remove the magazine. With the design used for the Glock, and a number of other blowback action air pistols, you mostly see the firing mechanism fixed to the frame under the slide and an opening where the top of the magazine fits. When you look at a CO2 model that has an operating system duplicating most of the J.M. Browning design, and we’ll use the Umarex S&W M&P40 as an example, you see the business end of CO2 mechanism, but below that you look straight out the bottom of the grip. This design also allows authentic field stripping of the gun, whereas the Glock-type system does not allow you to disassemble the pistol at all.

This is better shown with the Glock CO2 model loaded (left) and with the magazine removed (right). When the magazine is inserted, the locking bar (shown at right with the slide locked open), fits into an opening in the top of the CO2 BB magazine. The magazine itself is easy to load with a solid locking follower and direct loading through the firing port. Capacity is 18 steel BBs, equal to the standard G17 magazine plus one round chambered (17+1) to provide equal capacity to the 9x19mm model.

Is there any upside to this? Remember that word I hate to use, “compromise”? A shorter blowback design doesn’t use quite as much CO2 to operate and the upside is a little higher velocity. Most blowback action BB models using a Browning-style design have an average velocity of 300 to 320 fps. The Glock hits an average of 365 fps, the report is medium-loud and there is enough kick in the action that you know you have pulled the trigger on a fairly powerful CO2 pistol. In other words, it is a very good “compromise”.

3 thoughts on “First Look at the Umarex Glock G17 Blowback Action Model”

  1. nice job on this pistol. I will get one for three reasons. Just to be familiar with handling a Glock , which I don’t own, two because it appears to be an excellent replica pistol, and three while I never had the desire to own a striker fired , Tupperware pistol , I could see one application for it. Home defense , when coupled with my recently purchased Ruger PC Carbine. The Ruger is a takedown carbine that has a a mag well that allows the use of Glock mags. That lets you have a handgun and carbine that use the same mags. If Umarex were really smart , they would offer a Ruger PC carbine airgun that uses the same mag as the Glock 17 pistol. Good for training and for action airgun matches

  2. Hey! Dennis,
    Not here often…but have enjoyed very much reading (and learning) your Reviews. I like the honest accuracy and the historical (when required) background you go into with your writings.
    I was hoping to see a ‘pellet’ version…but maybe that’ll come later on from Glock (Umarex). I did get the G19 for the sake of having one in my modest collection. It is in fact quite accurate for a BB airgun pistol. By the way…I still have a Umarex SA117 which was the first ‘G17 look-a-like’ CO2 BB airgun pistol with Blowback. Admittingly it’s not an actual reproduction (replica) as this new version G17 BB CO2 pistol.

    I’d like to go back to your comment about the ASG Holster. The PA catalog claims it will ‘fit’ the G19 (and others). You’re absolutely right about the questionable fit and I have found the problem and the solution for the (tight fitting ) holster I purchased from PA. It does require a slight modification and some light sanding down to function flawlessly afterwards. I discovered that the restriction came mostly from the holster area encasing the bottom part of the pistol’s trigger guard. If you look real closely in that area of the holster you should see 2 thin ‘raised ridges’ or ‘tracks’. They apply too much restricting force on the bottom of the G19 pistol trigger guard. I went about removing them with a narrow wood chisel and shaved them off completely. That gave me a 90% improved fit. I also hand sanded the internal sides of the holster where the polymer frame of the pistol starts to make contact with the holster. Not much is required to sand but with some 150grit work on both sides…it did the trick. The G19 BB pistol now ‘glides’ in and engages the Retention lock. Extraction if smooth and quick with finger pressure on the Retention release buttom.
    Hope this may be useful.
    Looking forward to Part 3.


  3. Dennis, when u shot this GLOCK did u have any issues with a slide bite? I have a Gen5 in 9mm, and I put the backstrap with the beavertail on it. I’m just leery of my hand slipping high and getting bit. Also have you heard anything on if the Gen4 model will take the backstraps from the actual firearm? The pin hole is there in the picture but it might just be a faux look. I have a couple spares left over from my nine sitting on the workbench shelf collecting dust. Be nice to use them.

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