Welcome to my review of the Glock 34 MOS 9mm pistol, and a discussion on whether it is worthwhile to add a red dot to your pistol for competition or defense. Bear in mind though, that the technical aspect of the review will not focus on Glock vs. Smith and Wesson or any other pistol platform, but more about the utility and design of the Glock MOS, modular optics system.
The review is organized into the following sections:
Optics on Pistols- What's Been Done and What's to Come
Shooters have been doing custom milling to install red dots on their Glock slides for years, but 2015 was the first year that Glock had a factory-produced model with a slide cut to accept a red dot. Last year, US customers could only get the competition and hunting models with the MOS, but now the 17 and 19 have options for the MOS. Before that, Smith & Wesson had M&P models that were factory-cut for red dots, and FN made the FNX Tactical in 45 ACP with cuts for a slide-mounted red dot. From my research, as of the recording of this video, these are currently the only factory model centerfire handguns that can accept a red dot mounted deep within the slide. The Canik TP9 is getting a budget race gun makeover with its slide cut to accept a red dot, which should be available sometime in 2016. Reports of the Sig Sauer P320 RX, a P320 with a factory-installed Sig Romeo Red dot, have been floating around since early 2015, and Cabela’s even had a listing for them on their website for a while, but the release date kept getting pushed back. They might finally be launching in 2016. [APRIL 2016 Update- The Walther PPQ Q5 Match is now shipping to distributors.]
Glock Modular Optics System Technical Details
The MOS mounting system itself is not very robust. The MOS slides had to sacrifice some mounting security in order be adaptable to a variety of optic choices. You only have about 2 threads of engagement when securing the mounting plate to the slide and when securing the optic to the plate, so loctite is critical. The Glock screws are flimsy and easy to strip. If you want to use the Trijicon screws, you have to buy a spacer (Amazon link). I’m not a Glock engineer, but I do feel as though the MOS design was rushed to market. Then again, it may be possible that this was the only configuration that made it possible to accommodate different optics. CZ Custom did manage to mill a P-09 slide to accept different optics without the need for mounting plates. My RMR has still kept its zero and remained rock-solid, but I wouldn’t use the red dot as a slide racking aid unless I absolutely had to, What I don’t have a problem with is the mounting depth. Some shooters would prefer the RMR to sit lower within the slide, but I feel the MOS height is the perfect balance in providing co-witness when needed and preventing the suppressor-height sights from being too obstructive when not needed.
Save for the optics cut, the Glock 34 MOS is virtually identical to the Glock 34 Gen 4. The barrel is 5.31 inches long. The slide has one large port, to keep the upper assembly mass closer to the Glock 17’s, as to not require as much fiddling with recoil springs for timing. The factory 17 pound recoil springs are interchangeable between the Gen 4 Glock 17 and Glock 34. The recoil spring assembly has a captive polymer guide rod wrapped with dual-springs, a feature of Gen 3 subcompact and all Gen 4 Glocks. The gun comes with adjustable polymer sights, which will not co-witness with any optic, so I swapped mine out for the Ameriglo suppressor height sights (Amazon link). The fire-control group has the Glock minus connector already installed, so the trigger should break closer to 4.5-5 lbs instead of the standard 5.5-6 lbs.
The “brass-to-face” problems of the Gen 4 Glocks are also present on the Glock MOS, but I feel it’s more problematic due to the reduced slide velocity from the added mass of the RMR. If you remember from my shooting clips, you can see the brass roll off of my forearms. That was with Freedom Munitions 135 grain factory new loads, which tends to be slightly underpowered. Winchester white box also has similar ejection patterns. These are all American-spec economy-grade ammo. European economy grade 9mm, like from PPU, Magtech, S&B, and Perfecta, run hotter loads, and eject casings with more force than American-made economy grade 9mm. I did get some brass-to-face within the first 400 rounds when shooting Perfecta from Wal-Mart, but after more breaking in, the ejection improves to where you don’t have to worry about any more brass to face.
Overall, I’ve not had problems with reliable cycling. I did have one malfunction, but that was on my first range trip, with Freedom Munitions’ underpowered ammo, using a Glock factory magazine pinned to hold only 10 rounds. The pin stops the spring’s regular decompression, so I was lucky the gun even cycled at all. I’ve since gotten some aftermarket magazines from a Virginia gun show. The Magpul ones are good to go, but the ETS ones are not.
Philosophy of Use (POU)
The Glock 34 is not going to be my primary competition pistol, because I shoot in the tac-optics division, and you would have to move to the open division if you wanted to use a pistol with an optic. The reason I still wanted a centerfire pistol that was factory-milled to accept a red dot optic was to add a new dynamic to my training. With a parallax-free red dot optic, the sight alignment fundamental of shooting proficiency becomes a non-factor. It’s easier to shoot with both eyes open, but both eyes open shooting is a skill everyone should develop early and often, as you’ll have better situational awareness and less muscle strain. You are all-but guaranteed to quickly acquire a clear sight picture when looking through a red dot, versus when aligning iron sights (or polymer sights, if you’re using the Glock factory sights), when you have to pound it into your brain to bring the front sight in focus, which blurs out the target. I found that getting proper sight alignment was one of the reasons that I hesitated before taking my first shot after drawing. I’m cross dominant, mean that even though I’m right handed, my left eye is my dominant eye, resolving the straight-on focal point, and the right eye gives an angled view for depth perception. Instead of squeezing my left eye closed, I tilt my head to align my left eye with the sights so that I can shoot with both eyes open. The parallax-free red dot sight make sight alignment a non-factor to my speed and accuracy, so I can concentrate on other fundamentals, like trigger squeeze and muscle coordination. With more practice on those fundamentals, it allows me to go back to a gun with iron sights only, with the confidence in knowing that I have the muscle memory for correct trigger squeeze and muscle coordination, so now I don’t have to devote any of my active thinking to anything except sight picture and getting rounds on targets quickly.
I’ll try not to sound like I’m exaggerating or overstating the benefits (I’ll probably fail though), but simply put, a red dot on a pistol is a game changer. Whether you are a sponsored competitor who makes a living from shooting sports, or you’re just a novice starting out, shooting with a red dot instead of iron sights improves your speed and precision. I’ve had so many people try out my Glock MOS and say “I’m normally horrible with a Glock, but there’s no way you can’t not shoot well when you have a red dot that does all the work for you.” There’s no learning curve to using a pistol with an optic- just like with a rifle, you put the dot where you want rounds to hit and let them fly. The smaller dot, 7.0 MOA in my RMR, allows you to get tighter group sizes on paper and hit precision targets that the thick front sight post would have covered up entirely.
Although a red dot can enhance existing skills, it cannot offset or replace the importance of pistol training fundamentals. Red dot or not, if you want to be shoot quickly and accurately, the same pistol handling mechanics are important. When drawing, you can’t just extend the pistol and look for the dot (i.e., "chasing the dot") because the window is way too small. You would have been faster to get on target just using the iron sights. When drawing, you still have to index your dominant eye on your front sight when presenting the gun toward your target, but once your optic comes reasonably aligned with your front sight, the dot will come into view, and you can now shift your focus to the target. As a cross-dominant shooter, even though I can align the optic over my right eye, I still choose to aim with my left eye because it’s how I index on the front sight, and it’s much faster to reacquire the dot after the slide cycles.
Although everyone will benefit from shooting through an optic instead of iron sights, the degree of improvement will vary based on the shooter’s experience. A high-volume shooter with years of pistol training will only see sight improvement, because sight alignment is second nature to them. Hickok45 is a cross-dominant shooter, and he shoots better with irons than most shooters can shoot with a red dot. A novice shooter using a red dot pistol can easily halve their time and double their accuracy. The type of targets also make a difference on how much your performance will improve. For torso-sized targets at common defensive ranges, you’re not going to notice any difference. For poppers or smaller plates at 25 yards, you’ll definitely appreciate having a red dot sight. It’s important to have realistic expectations based on your shooting experience and the type of shooting you will do at the range.
You can also close your performance gap using a pistol with irons-only by upgrading to a set of quality competition sights. Most factory pistols come with 3 dot or non-contrast sights, which make it harder to index your vision on just the front sight when it’s easy for the rear sight to pull your eye’s focus away. Going with a blacked-out rear and a large, bright front sight is a massive improvement. Here’s me shooting my CZ with an upgraded trigger and competition sights. I didn’t measure with a shot timer, but the performance comparison seems similar enough to what I can manage with the Glock’s stock trigger and RMR. Try upgrading to competition sights before deciding on a red dot pistol. You might improve enough that you feel like you won’t need a red dot to reach your performance goals.
The Glock with the RMR has met all my expectations for performance at the range, but for real world defensive and carry use, how much benefit would a pistol with a red dot have over a pistol with only iron sights
Keep in mind, that I have no military or law enforcement background, and all of my thoughts about defensive use come from literature review. In real world defensive shooting situations with pistols, very little shooting is actually precision aimed shooting. Microseconds count in a deadly force situation. You simply don’t have the time to get sight alignment like you’re in a bullseye match. The maximum range at which most pistol defensive shootings occur is seven yards. Even without seeing the sights, point-shooting, which is literally just pointing the gun in the assailant’s direction and squeezing the trigger, is good enough to reliably hit center mass enough times through half a magazine to stop the assailant. Proficiency on the range doesn’t translate into effectiveness in a deadly force situation. In data from the NYPD SOP 9 report, which is one of the most comprehensive sources on police shooting statistics, officers who were in the higher percentiles on range scoring had no statistically significant advantage in hit percentage in defensive shootings compared to officers who were at the lower end of the range score spectrum. The hit percentage against assailants without a firearm is about 30%, and in gunfights, the hit percentage can drop down to as low as 11%. And yes, most of the data comes from before the NYPD adopted the heavy Glock triggers. That’s not to say that you can’t train to improve your performance under stress- it’s just that training for bullseye precision isn’t representative of the instinctive shooting skills you need to develop, and a red dot won’t help you get there. Nothing can replace proficiency in defensive shooting fundamentals.
Therefore, the ability to have a red dot on your pistol should not be a major factor in deciding on a pistol for defensive use. However, I can’t think of ways having a red dot could negatively impact a pistol’s defensive performance. I’ve searched for data on whether any United States police departments have approved red dots on duty pistols, and please correct me if I’m wrong, but I’ve not found any that have given department-wide blanket authorization for red dots on duty pistols. There have only been individual forum posts from “officers” who have outfitted their duty pistol with an optic. But again, you have to take these posts not just with a grain of salt, but pick up the entire salt shaker and go to town because who knows how many of these “officers” are actually LEO and how many are like the stolen valor people, living vicariously through the sacrifices of others. That’s a mental health issue that would take way too long to finish discussing in a gun review video...Moving on, I’ve only seen one source on the Glock MOS used in military service, aka “seen in the wild,” and that’s from Greek forces. Even so, I feel that putting a red dot on a pistol is gameplanning for .01% of tactical scenarios where a red dot would actually matter on a pistol. Again, I can’t see it being a detriment, but for duty or service use, if you’re in a situation where you have the time to aim down sights, and you need the precision of a red dot, then the situation would be better resolved with a shotgun or rifle,
So why in particular would you want to choose the Glock 34 over the Glock 17 or Glock 19 MOS? With an optic, the increased sight radius of the full-frame models is worthless. For defensive considerations, you might get 15 FPS more bullet velocity going from the 4 inch barrel of the Glock 19 to the 5.31 inch barrel of the Glock 34. So is there any reason to choose the full-frame Glocks, when the Glock 19 is arguably a better fit for most shooters’ hands, easier to carry, and easier to point-fire? I still chose the Glock 34 because for me, carry comfort is a non-factor, so I chose the Glock 34 for the slight edge in shooting comfort and controllability over the Glock 17. The difference in recoil is going to be subtle, probably not enough for most to justify the added size of the 34 over the 17, but I favor anything that minimizes shooting fatigue over high round count range sessions. Talk to any benchrest shooter about the effects of accumulated recoil. Most of the F-Class benchrest community has a money-no-object approach to their equipment, but there’s a reason why you don’t see much 338 Lapua or other magnum action calibers in F-Class matches, and why short action calibers continue to set records. It doesn’t matter if you’re Marcus Luttrell or Bob Lee Swagger, cumulative felt recoil affects your mechanics, and you can get sloppy until you sleep it off. The same concept applies to pistols. Minimizing felt recoil over the course of a long, high round count shooting session keeps your skills sharper, and you won’t have as many misses in the later stages.
So is there any point to choosing the Glock 19 with an RMR? Without MOS considerations, many choose to get the Glock 19 because of its ease of carry and/or concealment over the Glock 17, and the grip is a better fit for most, but having a red dot increases the pistol’s profile and could print through some clothes, minimizing the advantages of the compact form factor, so you have conflicting design choices that minimize the strengths of each. You reduce compactness, and you don't have controllability of the full-frame Glocks to take optimize for the speed advantage of shooting with an optic. For an all-in-one gun- home defense, carry, and target shooting- the Glock 19 is still a viable option. As mentioned earlier, you are not hindered by the shorter sight radius of the compact Glock because you now have an optic. The difference in recoil intensity going from the Glock 17 to the Glock 19 is much more noticeable than the recoil difference in going from the Glock 34 to the Glock 17, but the snappier Glock 19 is still very controllable for typical defensive ranges, but will require more time to get back on target for competition style courses of fire.
Accessories, Upgrades, and Value
There are no shortage of options for Glock modifications, but how many of them are actually upgrades? Some Glock owners just want an improved trigger, and some Glock owners want the whole race gun treatment. So I feel like I’m going to rustle a lot of jimmies with my suggestions on Glock modifications. Many Glock accessories on the market drastically reduce the reliability and their parts do not pass the long-term durability test of Glock factory original parts. And here’s where the comments start flowing with “I’ve got this upgrade kit and it’s worked flawlessly through x number of rounds.” Good for you. The reality that many Glock tuners don’t want to face is that Glocks are harder to tune than hammer-fired pistols. With the few number of action components, each part has a greater relative importance. The design specifications have a much tighter tolerance to allow each part to do double duty while ensuring proper clearances and correct timing. Domestic startup firearm manufacturing companies simply don’t have the overhead to perform the industrial-level reliability testing that Glock does, and if you think they do, then you’re deluded. Firearm accessory manufacturing has a slim overhead, with smaller companies flirting with being in the red year round.
It’s not to say that Glocks cannot be reliable race guns. It just takes a ridiculous amount of dedication that the average enthusiast cannot devote. The race guns are often tuned to a custom handload, and will choke on any other ammo. Even then, in matches I’ve gone to, I’ve seen Glock race guns choke the most, even for a shooter with more experience than me shooting their custom handloads. If you want your Glock to have the same reliability that Glock built their reputation around, then I cannot in good conscience recommend you pursue modifying your Glock’s action. You don’t have to listen to me. I’m a literal nobody in the world of firearms. But I’m just saying that the Glock accessory market is the perfect embodiment of just because of you can, doesn’t mean you should. Again, this is a touchy subject, so I’ll just let it go for now.
To mount your red dot, you can also use a rear-sight dovetail or rail mount. Are these reliable or effective? Maybe. Sorry I don’t have a more in-depth opinion. You do definitely lose the, here’s another fancy nuts term, “second kind of cool” from using the MOS system.
You can choose to get your slide custom-milled for a red dot, but please go to a reputable gunsmith. I’ve seen a lot of botched milling jobs, with poor alignment or cuts so deep that it exposed the striker spring. If you don’t already own a Glock and want one that accept a slide-mounted red dot, then there’s almost no reason not to get the MOS model. It comes in at a lower price than getting the custom milling work, and you don’t have to destroy the resale value of the Glock that you send for custom milling.
The tac-light I’ve been shooting with is the Inforce APL (Amazon link). I choose this one over competing models because of its affordability and because it only uses 1 CR123A battery, helping to cut down on weight. The Glock 34 is the only pistol I can tolerate shooting with a tac-light. The loaded pistol without the tac-light already has a well-balanced feel, with the large port on the slide minimizing a front-heavy weight distribution, so the tac-light actually works as a counterweight in reducing muzzle jump. With some more top-heavy guns, like the CZ P-09, shooting with a tac-light actually feels like you’re just adding more inertia to the gun when it recoils, increaing both the muzzle jump and the the muzzle drop when the slide returns to battery. With a tac-light equipped glock, I do feel as though it’s a little slower to get on target because of the increase overall weight of the pistol, but getting successive shots on each target is much easier due to the reduce muzzle jump.
The custom kydex holster I ordered for the Glock 34 MOS with the Inforce APL is the Duty KT Azalea with a sick Kryptek Mandrake camo pattern. I opted for a thumb break for active retention and Blade Tech’s Tek-Lok for the belt attachment mechanism. KT holsters are already fitted for suppressor height sights. There are some holster designers, like Safariland, that offer Glock MOS holsters that cover the optic entirely, reducing the chance that the optic will snag and knock the slide out of battery.
In summary, the Glock MOS platform gives the shooter many options for mounting their optic of choice. Shooting with a red dot can be a game changer, depending on shooter experience and the type of target. For defensive applications, the option to add a red dot should not be a deciding factor in weapon choice. Glocks have a much-deserved reputation for reliability. Please don’t buy a Glock with the primary intention of modifying the trigger or action. That’s not to say you should rule out ever modding your Glock, but if the only way you can enjoy shooting a Glock is if it has mods, then the gun isn’t for you.