Glock 34 MOS Gen 5 – Video Review

U.S.A.-( Since the Glock 34’s introduction in 1998, it has become a favorite of shooters seeking higher muzzle velocities, a longer iron sight radius, and the ability to keep a weapon light lens a bit cleaner. Sure there are a ton of other reasons that someone might choose the Glock 34 over the Glock 17 but those seem to be the most common ones.

GLOCK 34 MOS Gen 5

The Glock 34 Gen 5 makes the third generation of G34 that we have seen and has its fair share of updates that place it in line with the rest of the Gen 5 lineup. The flared magazine well, improved trigger and barrel, ambidextrous slide catch, and new sight options should make potential buyers of the Gen 5 Glock 34 very happy.

The MOS System

With red dots on pistols becoming more prevalent than ever, Glock almost HAD to introduce the Gen 5 Glock 34 with the MOS plate system right out of the gate. While the plate system isn’t as secure as some other mounting methods, it does offer a high degree of flexibility while keeping overall costs reasonable.

A Shield RMS mounted on the MOS slide.

While most are pretty familiar with the MOS system, I feel that going into the pros and cons of the system is an important aspect of the review.


  • Allows the end user to mount a mini red dot (MRDS) directly to the slide of the pistol.
  • The four included adaptor plates provide a pretty wide selection of MRDS to choose from.
  • Installing a red dot is very easy and only requires basic tools.
  • Aftermarket plates are available that place some red dots like the Shield RMS low enough to co-witness with standard height sights.


  • The MOS adaptor plate can become loose over hundreds of rounds and cause the pistol to lose zero.
  • Tightening the adaptor plate requires removing the red dot and will result in a lost zero.
  • The required adaptor plate prevents the red dot from sitting as low as when the slide is custom milled for the red dot.

That said, the MOS system is serviceable as long as you understand the potential drawbacks, ensure you use blue Loctite and make sure your screws are tight on a regular basis.

Gen 5 Updates & Features

The Gen 5 pistols from Glock expands on the improvements seen on the Gen 4 gun with a new ambi slide stop and a magazine well for the full-size frame models and they removed the finger grooves from all models as well as added the Glock Marksman barrel. There are a ton of other changes made internally like a beefer striker, a new trigger bar, and other small parts changes that come together in the form of a much more refined pistol.

The Glock 34 Gen 5 roll marks.

As you might guess, the upgrades are a direct result of the Glock 19M and 17M development for the FBI pistol trials. Glock made even more tweaks to the pistol and rolled it out to the civilian market as the Gen 5 Glock.

In addition to the standard MOS plate system, Glock also removed the large window at the front of the slide on the Gen 5 guns. Sadly I don’t have a Gen 5 Glock 17 or a Gen 4 Glock 34 to compare slide weights. Even though it I wouldn’t call it the most reliable information, what I found on the web suggest that the slide mass has not changed from the Gen 4 G34.

The Glock 34 Gen 5 field stripped.

The Gen 5 guns get a brand new coating called NDLc that should improve performance in adverse conditions as well as reduce the possibility of holster wear or scratches. Glock has also added the Marksman barrel to the Gen 5 guns that reportedly increases accuracy. The only way to really know is to get the gun out to the range.

The First 1,000 Rounds

I have a really bad habit of modifying guns within a few weeks of getting them, the Glock 34 Gen 5 was no different. I was able to get a range day in with the pistol in stock form and found that I really loved how it felt. Had the good idea fairy not struck, the pistol would have stayed completely stock.

First targets right out of the box were rather good with accuracy better than I have seen from stock Glocks in the past. The Marksman barrel really seems to improve how the pistol shoots when paired with the improved Gen 5 trigger’s improved trigger break. After 200 rounds downrange in stock form, I sent the pistol off for the framework.

The Glock 34 Gen 5 magwell.

Since you aren’t allowed to add a magwell in Carry Optics and the Glock 34 Gen 5 is legal in that division, should stippling the frame and closing that cutout in from up to finish out the magwell give a competitor an edge? I called my friend Tom at TXT Custom Gun Works who does just about all my stipple work and ran the idea by him. Not only did he love the idea, but he also said he would give it a try. Tom attempted to plastic weld a plug to complete the magwell but I was too rough on it for the mod to last. Not that big of a deal, I found that the cutout in the front of the grip didn’t impact my mag changes at all. Tom also stippled the frame with my preferred pattern, something that he calls cross-hatching. While the factory texture on the grip is perfectly fine the addition of material to close up that gap made it an almost requirement.

While my plan of creating a “cheater” Carry Optics gun didn’t work, the Glock 34 shot very well over the next 800 rounds of mixed range ammo with only a few issues with the MOS mounting system.

TXT Custom Gun Works’ cross-hatch pattern on the Glock 34.

I didn’t experience a single malfunction that wasn’t deliberately set up to test the Shield RMS red dot I have mounted on the Glock 34. While I will go into more detail in another post, the Shield RMS is perfectly fine for range and competition use but I wouldn’t recommend it for defensive or duty use. Look for a full write up soon.

What Do I Think?

After over 1,000 rounds down range, my thoughts about the Glock 34 Gen 5 MOS are mostly positive. You are going to get the obvious gripe about the plate style MOS mounting system that continually came loose while shooting. While that may have been the fault of the thinner plate from Shield, it still was really annoying. I am not ready to say that my experience with the Shield RMS was a failure so much as it was me using it outside of its intended competition role, but again, we will get into that in a separate review later.

The Marksman barrel offers a noticeable improvement in accuracy.

The only thing that could have made the Gen 5 Glock 34 MOS better? Offering a Gen 5 Glock 34 that comes without the MOS system. Sure, you can just run it with the cover plate, but I would have much rather been able to send the slide off to a machine shop and have it milled for my choice of optic. Since the MOS cutout is larger than my preferred Trijicon RMR that really isn’t an option now.

Aside from the issues with the MOS plates that may have been the fault of the aftermarket Shield adaptor plate, I feel confident in saying that the Gen 5 Glock 34 is the best out of the box Glock to date.

What Does It Cost?

The Glock 34 Gen 5 MOS will run you $899 if you happen to pay MSRP. Street prices seem to be hovering in the area of $720 or so at online retailers like Brownells.

If you would like to know more about the Glock 34 Gen 5, head on over to the Glock website.

About Patrick R.Patrick Roberts

Patrick is a firearms enthusiast that values the quest for not only the best possible gear setup but also pragmatic ways to improve his shooting skills across a wide range of disciplines. He values truthful, honest information above all else and had committed to cutting through marketing fluff to deliver the truth. You can find the rest of his work on as well as on the YouTube channel Firearm Rack or Instagram at @thepatrickroberts.

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No LocTite on the adapter plate screw threads?