New for 2023 is a trio of fresh Gen 5 models, including an update to the company's much-loved double-stack .45 ACP. 

Introduced officially at SHOT Show last month in Las Vegas, Glock debuted the new (at least to the consumer market) Gen 5 G47 in 9mm, as well as 5th Generation variants of the legacy G20 10mm and G21 .45. 

The new Gen 5 G21 has lots of generational updates to a very familiar pistol. (All photos: Chris Eger/, except where noted)


A little history on the G21

Glock first announced the G21 back in 1990, in a host of caliber changes that offered more than the company's 9mm initial offerings-- the G17 and G19. Announced that year were the aforementioned G20 and G21 along with the .40 S&W caliber G22. At introduction, these were 2nd Generation guns, a series only gently updated from the company's original debut in the mid-1980s.  

I've been fooling with the G21 off and on for almost 30 years. My first was a Gen 2 AAZ-serialized G21 that I picked up in 1994, just as the federal AWB and magazine cap kicked in that chopped the standard mag capacity from 13 rounds to just 10. I kept that tough-as-nails .45 through Hurricane Katrina, during which and immediately after it was never far away, and only passed it on to its current owner in 2006, downgrading to a 9mm as my everyday carry. 

Glock 21 Gen 2 .45ACP pistol
My first G21, a Gen 2 model, is seen here in a low-res circa-2005 image. It worked when I picked it up 11 years before, ran everything I fed it in the interlude, and it is likely still working wherever it is today. Note back then they didn't even have thumb grooves in the frame or an accessory rail. 

Then came the Gen 3 Sport/Service models in 1997, which brought with them recessed thumb rests, finger grooves molded into the frame, and, eventually, an accessory rail.

The Gen 4 G21 arrived in 2011 with the company's improved RTF-4 texture, interchangeable frame back straps, a reversible enlarged magazine catch, a dual recoil spring assembly, and a new – some would say improved – trigger.

Glock 21 Gen 4 .45ACP pistol
The Gen 4 G21, here seen in its more limited Olive Drab frame variant. (Photo:

And since then, the G21 has been frozen in time, locked in 2011, although Glock threw fans a bone with limited-run batches of FDE, OD green, and gray framed subvariants. In the meantime, the company introduced their 5th Generation guns – but only in 9mm (G17, G19, G19X, G26, G34 and G45), .40 S&W (G22, G23 and G27) and .22 LR (G44).

Now, Glock finally reached back and brought the old "large frame" 10mm and .45 full-sized pistols into the present. 

What the 5th Gen brings to the G21

While keeping the same 13+1 round magazine capacity (although not with backward compatible magazines), and overall rough size and shape as previous generations of G21s, the new model drops the finger grooves on the grip, adds a gently flared magwell for faster reloads, and comes standard with ambidextrous slide stop levers. 

Glock 21 Gen 5 .45ACP pistol
Note the straight-profile grip closer to that seen on the Gen 2 guns, albeit with a more modular frame due to the ability to use interchangeable medium and large backstraps, and with a more modern RTF polymid texturing. 
Glock 21 Gen 5 .45ACP pistol
While I loved Glock's old hyper-aggressive RTF-2 texture – which was only offered in family on the 21SF subvariant for a couple of years – the newer RTF-4 texture is still effective. 
Glock 21 Gen 5 .45ACP pistol
Another new feature on the Gen 5s is forward slide serrations.
Glock 21 Gen 5 .45ACP pistol
On the inside, the 5th Gen guns use the new Glock Marksman Barrel with what the company says is a more aggressive polygonal rifling with a target-style crown and tighter chamber specs. The G19X and G45, which also use a GMB, have proven exceptionally accurate on the range in past evaluations. 

Glock has tweaked the 5th Gen triggers for a smoother pull and improved reset over past generations. Sadly, while the company announced its new flat-faced Glock Performance Trigger at the same time as the trio of new 5th Gen guns, the enhanced trigger isn't included on these guns yet – and won't be an option for the G21 as the new pack is for 9mm pistols only.

Glock 21 Gen 5 .45ACP pistol
We found the stock 5th Gen G21 trigger to break right at about 5.5 pounds with a half-inch travel and a short reset. 
Glock 21 Gen 5 .45ACP pistol
With a 4.6-inch barrel and an overall length of slightly over 8 inches, the Gen 5 G21, left, runs slightly longer than its full-sized 9mm cousins, the G17 and G47. 
Glock 21 Gen 5 .45ACP pistol
In size, the newest Glock .45ACP is just shorter than the common M1911 Government but only weighs 29 ounces (unloaded), which is a half-pound lighter than the unloaded weight of most steel-framed 1911s. 


Optics ready

A big bonus on the Gen 5 G21 is that it comes Modular Optics System, or MOS, standard. That is a first for the pistol, as users had to get their slides milled in years past. The only .45 ACP in Glock's catalog that came with the MOS package until this year was the practical/tactical Gen 4 G41 longslide.

Glock 21 Gen 5 .45ACP pistol
The cover plate is also now plastic rather than steel.

Whereas Glock pistol models in standard MOS configuration previously came with four numbered DLC-coated steel adapter plates and hardware in a blister pack, newly announced MOS series guns – the G20 Gen5 MOS, G21 Gen5 MOS, and G47 MOS –  will only come with the No.02 plate that will fit Trijicon, Ameriglo, and Holosun (except 509) pattern red dots. The others will be available from Glock for about $10 each. 

Glock 21 Gen 5 .45ACP pistol
Other than that, the G21 still carries Glock's traditional $12 U-notch rear and white dot polymer sights. 
Glock 21 Gen 5 .45ACP pistol
The MSRP on the Glock Gen 5 G21 is $745, a figure likely to be lower at retailers. 

We've got an initial 100 rounds through the new Glock .45 on the block with zero issues to report and will be back with a full review as soon as we up that round count significantly.