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Umarex Glock 17 Gen 4

The original pistol and history

Glock is a brand of polymer-framed, short recoil-operated, locked-breech semi-automatic pistols designed and produced by Austrian manufacturer Glock Ges.m.b.H. The firearm entered Austrian military and police service by 1982 after it was the top performer in reliability and safety tests.

As the name suggests, the Gen 4 is the fourth in line, updates centred on ergonomics and the recoil spring assembly. The initial two Gen 4 models announced were the full-sized Glock 17 and Glock 22, chambered for the 9×19 mm Parabellum and .40 S&W cartridges, respectively. The pistols had a modified rough-textured frame, grip checkering, and interchangeable back-straps of different sizes. “Gen4” is stamped on the slide next to the model number to identify it.

Mechanically, fourth-generation Glock pistols are fitted with a dual recoil spring assembly to help reduce perceived recoil and increase service life expectancy. Earlier subcompact Glock models such as the Glock 26 and Glock 30 have already used a dual recoil spring assembly that was carried over to the fourth-generation versions of those models. The slide and barrel shelf have been resized, and the front portion of the polymer frame has been widened and internally enlarged, to accommodate the dual recoil spring assembly. The trigger mechanism housing has also been modified to fit into the smaller-sized grip space.

The introduction of fourth-generation Glock pistols continued in July 2010 when the Glock 19 and Glock 23, the reduced size “compact” versions of the Glock 17 and Glock 22, became available for retail.

TV and film

The Glock 17 is another widespread movie star with hundreds of appearances listed including Green Zone, Man On Fire, The Matrix, Mission Impossible 3, Paycheck, Taken and Quantum Of Solace.


  • Calibre: 9x19mm Parabellum, 10mm Auto, .22 LR, .380 ACP, .40 S&W, .45 ACP, .45 GAP, .50 GI
  • Capacity: 6 to 33 round box magazines or 50 & 100 round drum magazines
  • Weight: 680g
  • Length: 195mm

The CO2 Replica

Being a fully licensed replica, the Umarex Glock 17 Gen 4 was expected to be a close representation of the real firearm. I was pleasantly surprised and impressed when I found it to be an exact copy, even the slide markings are correct and not altered to show its BB firing nature. There are no ugly white letters or warnings printed on the pistol.

The body is a quality polymer build with steel slide as in the original, it is field strippable and can be disassembled in seconds. The safety is built in to the trigger as in the real firearm. Operation is single action only and needs the slide racking to load the first round from the magazine. I have mine fitted with a little laser sight on the short picatinny rail under the muzzle.

The Umarex CO2 Glock 17 Gen 4 left side

The grip is positive and fits my hand nicely, Umarex even supply two other back-straps for a larger or smaller grip profile – changing the strap is very easy.

The Umarex CO2 Glock 17 Gen 4 right side

The magazine is also pretty much identical, it is heavy and holds the 12g CO2 and the BB’s. Loading the CO2 is a little more complex than usual replicas in that you have to depress a hidden pin to release the plastic lower cap, slide that off which then exposed the CO2 securing nut. Loading BB’s was also found to be an issue, see further down the page.

The full drop-out style magazine

The slide will lock open when the magazine runs out, just like the real firearm, even the ejection port is articulated and will drop into the slide when the slide moves back – attention to detail is stunning.

The slide locks back after the last shot.

As mentioned above, loading BB’s, for me at least, was a complete pain – the plunger is recessed so far into the magazine face that it was a fingernail ripping exercise to pull it down far enough to lock. To make matters worse, letting the plunger fly back when empty runs a real risk of smashing the little web of metal at the top of the magazine, as seen below, mine is already slightly burred.

My simple solution was to 3d-print a little loading plunger depressor 🙂 In use the rod is inserted down from the ejection fingers at the top and when the plunger is at the bottom it can be flipper over easily into the locked position and the too removed. It works perfectly and saves many fingernails, it’s also faster. Once the plunger is depressed and locked open, the BB loading is easy and a speed-loader can be used.

I can supply these tools at very low cost if you want one, just contact me for details.

In use the Gen 4 is a pretty accurate and the blowback slide gives plenty of realism on every shot. I tend to not run the CO2 out as it can result in a BB left in the chamber which will need clearing manually. Cycle time is fast and double-tapping the tin cans is great fun, this is an extremely accurate replica and glad I bought one.


  • Calibre: 4.5mm BB
  • Capacity: 19 rounds
  • Weight: 700g
  • Length: 200mm
  • CO2 Usage: around 50 shots at good power