TFB Review: The New Glock 21 Gen5 MOS

Matt E
by Matt E
TFB Review: The New Glock 21 GEN5 MOS

In the world of 45 ACP pistols, there are a number of options as well as styles to choose from on the market today, whether that’s a classic 1911-style firearm or something modern like an HK45 or the new FN 545. What most people overlook Is the Glock line of 45 ACP pistols so I decided to pick one up and give it a proper shakedown. Let’s take a closer look at the brand-new Glock 21 Gen5 MOS.



The new Glock 21 Gen5 MOS is the next model evolution of the Glock 21 line. This new Gen5 model comes with the removal of the finger grooves from the frame, front serrations, and the MOS system for easy installation of a pistol red dot. Another addition is the inclusion of the nDLC finish which helps with overall durability and rust prevention. The standard barrel comes in at 4.6″. The capacity of the flush-fitting magazine is 13 rounds.

With an unloaded weight of just under 26oz, it’s one of the lighter options for a full-size handgun chambered in 45 ACP. With the new Gen5 variation, the magwell has also been slightly expanded Just like all other Glocks, The pistol comes with 3 magazines, a magazine loader as well as a cleaning brush. The Glock 21 Gen5 MOS pistols are shipping now at the time of writing this article. MSRP is set to be $744.99.

Spec List

Price$744.99Firearm TypePistol
ModelGEN 5ActionSemi-automatic
TypeSafe ActionSizeFull Size
Caliber45 ACPBarrel Length4.61″
Capacity13 RoundsAccessories3 Mags
DescriptionOptics ReadySightsFixed Sights
SubcategoryPistols – Polymer FrameMaterialPolymer

Range Time

So far throughout my testing, I have had the new Glock 21 Gen5 MOS for roughly 6 months and took it out almost a dozen times to range sessions. Thus far, I have roughly 750 rounds through the gun in all different weather conditions to really test the durability of the gun. Some of the things that stood out to me right away were the overall feel, grip angle and lack of finger grooves. I really feel like the new Gen5 frames feel better in the hand and offer a much more comfortable grip than the previous generation with the finger grooves.

When testing out the new Glock 21 in snowy as well as rainy conditions, the lack of finger grooves makes it easier to grip with gloves or under adverse conditions. When installing an optic, the front serrations are a nice addition as well so you don’t have to put your hand around the optic glass and cloud up the objective lens. It may seem rather trivial but it’s a nice addition for people who would like to keep the glass clean of obstructions. When it comes to the trigger, the overall action is smooth without grittiness or feeling mushy. When using the trigger weight meter, the average trigger pull weight of the new Glock 21 is 5.5-5.65 lbs with a crisp defined wall and audible reset. The new Gen5 Glock triggers are an improvement from the previous generation.

Accuracy and Reliability

In terms of accuracy, I set up a bench rest at 25 yards to get as many variables out of the testing as possible. For the ammunition, I used 230gr Federal American Eagle, 185gr Hornady ammunition as well as 185gr Federal HST ammunition. With this type of testing, I would do three separate groups of 5 rounds to make sure I received consistent results. The group sizes ranged from .61-.94″ The most accurate rounds were the Federal HST with an average group size of .61″ and the American Eagle opening up to .94″. This new Glock 41 is pretty impressive when it comes to accuracy given the larger caliber.

When it comes to reliability, the new Glock 21 Gen5 MOS has been 100% reliable with all ammunition across the board. This is one of the points where Glock is known for having developed a reputation of being extremely reliable across the board. This reliability was flawless in the 750 rounds put through the handgun over the last 6 months which is reassuring. After my 6 months with the new Glock 21, I wouldn’t feel uncomfortable or worried in the slightest about depending on this firearm for self-defense or any other situation where I may need a firearm.

A Good Suppressor Host?

One of the biggest possibilities for the new Glock 21 Gen5 MOS would be the potential to become a fantastic suppressor host. With 13 rounds, the Glock 21 has a fairly substantial capacity for 45 ACP over a traditional 1911 with the standard 8+1 round capacity. With the availability in the coming months of aftermarket threaded barrels, suppressor height sights, and the MOS optics mounting system, it really is a great option.

Of course, there are plenty of other options with slightly more capacity or features, but the overall price of the Glock allows you to buy ammo or aftermarket parts for the same price as other options. This makes the new Glock 21 Gen5 MOS a good option for someone who wants to build a suppressor host without breaking the bank. The amount of aftermarket support makes it an easier option to create the exact gun you’d like to use as a suppressor host.

Overall Thoughts

The new Glock 21 Gen5 MOS has benefitted from a number of upgrades and changes such as the better trigger, front serrations, MOS optics cut and the new grip style. I personally think it’s one of the most underrated suppressor hosts and overall large caliber 45 ACP pistol on the market. This is one of the few handguns I plan on purchasing and enjoying after this review which should be a good representation of how enjoyable I found the Glock 21 to take to the range and I’m excited to see what aftermarket barrels come out for it to make this a viable suppressor host.

Check Prices on Glock 21 Gen5 MOS Pistols

What do you guys think about the Glock 21 Gen5 MOS as a higher capacity 45 ACP option? Is it a strong candidate to become a backpacking gun or suppressor host? I’d love to hear what you think so be sure to leave your thoughts in the comments below. If you have questions about the new Glock 21 Gen5 MOS or firearms in general, feel free to shoot me a message on Instagram @fridgeoperator. Stay safe out there and we will see you next time for another TFB review.

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Matt E
Matt E

I'm an avid shooter and love educating whether it's at my job or in the shooting community. I'm an average joe that really loves talking with other people about firearms and other passions.I'm active on Instagram on @fridgeoperator.

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2 of 31 comments
  • Sid Collins Sid Collins on Aug 29, 2023

    Might buy the slide when available and tinker with a red dot.

    I am very happy with Gen 3 and high vis sights.

  • Social_Artifice Social_Artifice on Aug 30, 2023

    Things I like, gen 5 Glocks, things I don't like, MOS slides...

    I don't like dots on pistols as a rule of thumb. And if I wanted to have on one their I'd prefer getting the slide custom cut to get that dot nice and low. I don't like height over bore to be a consideration with a pistol, or to have a higher center of reciprocating mass on the slide.

    Buying a pistol and then needing to buy a blank to send out to get a slide setup the way I want is RADICALLY more money than the old RMR cut costs on a factory slide.

    I just wish all gen 5 offerings came in a non MOS config.