Firearms Handguns Reviews

Glock G48 MOS

The Glock G48 MOS is a good reliable slimline 9mm pistol with a lot of potential to be a great conceal carry option. Some of the features leave a bit to be desired and may fall short of some folks' expectations.

As promised in the Project Glock 48 post, here are my first impressions of the Glock 48 MOS. I’ve delayed publishing this review for a little bit for a few reasons. First of all, I’ve been busy with a few other priorities and have spent limited time on the range with the pistol. Next, my little project has had, well, some mixed results. Admittedly some of these mixed results have been of my own making and I’ll cover them in a future post. However, I feel like I’ve spent enough time with the pistol to confidently say first impressions have been established. So let’s dive right in.

The G48 MOS is one of the three slimline design pistols offered by Glock at the time of writing. Like all of the other slimline design pistols, it’s chambered for 9×19. It is offered in a MOS and a standard variant. MOS stands for Modular Optic System which means it is ready to accept pistol mounted optics. Unlike most of the other MOS pistols offered, the slimline designed MOS pistols are cut to only accept micro-optics such as the Romeo Zero, the Holosun 407K or 507K, the RMRcc, or similarly sized micro optics. In fact, I was unable to find any optic mounting adapter plates sold directly by Glock. So without relying on aftermarket parts, one is limited strictly to red dot sights that adhere to the Shield RMS/SMS mounting standard. I’ll get more into this later in this review. For now, suffice it to say that the G48 MOS seems to be designed with the armed citizen in mind who is looking for a lighter smaller framed 9mm pistol for concealed carry.

For those familiar with Glock pistols, the best way I can describe the G48 is as the offspring of a G43X and a G19. The rest of this review should make it clear why I would describe it this way.

Out of the box, the G40 MOS came with:

  • A typical Glock hard-sided foam-padded pistol case,
  • a manual,
  • a plastic cleaning rod,
  • a nylon cleaning brush,
  • a plastic cleaning brush,
  • a cable gun lock,
  • two ten (10) round magazines,
  • and the pistol itself.

All the contents are standard for a Glock pistol. Let us take a journey over the pistol from the muzzle to the bottom of the grip.

At the very front we start with the muzzle of the 4.17″ match-grade Glock Marksman Barrel (GMB) found on Gen5 series Glock pistols. The barrel I found to be very accurate and I was quite pleased with it. At typical pistol shooting distances of say 3 to 10 yards, it was very easy to stack rounds on top of each other as long as I did my part. At slightly longer distances of say 15 to 25 yards, I was able to shoot some very respectable 1.5″ groups from a bench rest. I’m certain the barrel, or rather the pistol, is more accurate than I am, but overall I was very pleased with what it did on paper.

Ever so slightly behind the muzzle we find the slide which includes front and rear serrations. The slide width measures 0.87″ in width and 6.85″ in length. The net result is a nice thin slide that provides a respectable almost 6″ sight radius. The combination of barrel length, slide length, and sight radius is pretty much in what I consider to be the sweet spot for concealed carry. Granted this is very much my own personal opinion, but I find that length to be not so long that it’s uncomfortable to carry or hard to conceal, but long enough to remain very functional when shooting the gun.

The slide was topped off with the stereotypical polymer Glock sights. They are functional, but generally the very first thing that most Glock owners replace. The front sight has a small dot on it. The rear sight has this funky square “U” shaped white outline. I don’t know the history behind it and I can’t think of a pistolero that cares for the design. Some folks even question their durability since they are made of polymer. I won’t flat out say they are trash since they are functional, but I don’t care for them and will be replacing them as part of my little project. However, I didn’t prioritize them as an upgrade.

Right in front of the rear sight, we find the MOS cut and factory installed optic cover. As I mentioned, the optic cut is small and intended for use with smaller micro-optic sights. Without relying on aftermarket adapter plates, one is limited to picking a small micro-optic that adheres to the Shield RMS/SMS mounting standard such as, but not limited to, a handful optics offered by Shield, the Sig Sauer Romeo Zero, of the Holosun 407K/507K. There are a few other optics that don’t adhere to the mounting standard that will work with an aftermarket adapter plate like the RMRcc. However, larger optics like the RMR, while possible to attach with aftermarket adapter plates, might not be a good idea for a couple of reasons. First a larger optic will increase the overall width of the pistol which may not be desirable in terms of comfort. Additionally, some of the adapter plate options I found didn’t include recoil lugs which puts additional stress on the mounting screws and increases the chance of likelihood of failure. Last but not least, the adapter plates for larger optics raise the height of the mounter optic which limits choices in terms of back up iron sights. Folks who have their eyes set on larger optic should consider the non-MOS G48 and having it milled specifically for the target optic.

Below the slide we find the polymer frame which starts with Glock’s proprietary slim mounting rail. The accessory rail is a nice feature that is not found on the non-MOS G48 variant. However, its size and proprietary design will limit some of the accessory options to those that are compatible with the rail.

Behind the rail we find the trigger guard and the trigger. While the 5.5 lbs trigger feels better than earlier Glock triggers, it still has the stereotypical Glock trigger feel and function. The trigger works reliably. Many folks are perfectly fine with the trigger. However, I wasn’t thrilled with it and, as I mentioned in the project post, I ended up replacing it.

Just behind the trigger we find the magazine release button. While it is not ambidextrous, it is reversible for left handed operation.

North of the magazine release we find the slide lock (or slide release depending on one’s preferred terminology) lever. The slide lock lever is not ambidextrous and unlike the magazine release button, it is not reversible.

The combination of the slim frame and short trigger distance makes the slide lock lever and magazine release button a lot easier to reach for folks with smaller hands or meaty hands with shorter fingers. Another thing to note is that while the grip length is long enough for most folks to get a full three finger firing grip on the pistol, folks with larger hands or meaty palms may have a bit of palm hanging off the bottom that might get pinched during magazine changes.

The frame does boast a built-in beaver tail. However, I didn’t find it to be very pronounced and folks with meaty hands might catch a bit of slide bite during live fire operation.

In terms of shooting, as I mentioned earlier in this post, the G48 MOS is accurate. It’s certainly more accurate than I am and I suspect it is more accurate than most shooters. That said, I did find the G48 MOS a bit more difficult to control than I had expected. I am confident part of this is due to the lighter weight of the slimline G48 (which weighs 18.31 ounces unloaded) compared to the pistols I am used to shooting. In my opinion, the other contributing factor was the grip texture, or rather the lack thereof. The best way that I can describe it is that the pistol had more muzzle rise than I expected and I had to work at maintaining a solid two handed firing grip on it. I found myself readjusting my firing grip way more often than I wanted to.

While the G48 MOS is functional out of the box and will work just fine for most gun owners, it falls short in some areas which are the typical suspects Glock owners would expect. The silver lining is that the pistol is a solid foundation to build on and, as one would expect from a Glock pistol, there are plenty of aftermarket options available to address those shortcomings. Alternative options folks who are looking for a more turnkey ready-to-go pistol in this form factor might want to consider the Sig Sauer P365XL or the Sig Sauer P365X. Don’t get me wrong, it’s a good pistol and with a little work it has the potential to be a great pistol.


  1. The #1 reason to buy a G48 is if the frame of a G19 is too wide/fat for your hand, specifically the trigger reach. Those that want a RMR sized dot can buy a non MOS G48 and have it milled, as I did. C&H Precision Weapons did an excellent job milling the slide to accept RMR/Holosun 507 not-K sized sight. The overhang is slight and is not an issue at all for comfort or any other aspect of the pistol. Shield Arms S15 magazines solve the capacity difference between G19 and G48, although I recommend loading the S15’s to 14 vs 15 for best reliability particularly when seating a full mag with a round chambered.

    Having spent a lot of time comparing the SIG 365XL and G48, the big negative with the 365XL is recoil. It’s considerably snappier than the G48. The 365 family performs best with the aftermarket grip panels and grip weights (Wilson Combat makes a great grip module). Out of the box the 365 trigger is better than the G48 though.

  2. I have a G48 equipped with a 507K. It has proven to be a very good shooter for me. I actually used it in “Open” at a falling steel shoot and was far more confident than with the 17 I used in the stock division.

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