GEN 4 Glock 21

Glock pistols have become the company’s most profitable line of products as well as supplying national armed forces, security agencies, and police forces in at least 48 countries. Glocks are also popular firearms among civilians for recreational and competition shooting, home and self-defense, and concealed carry or open carry.” – Source: Glock Ges.m.b.H.

Advancing through several generations of Glock pistols, in 2010 Glock introduced the GEN4 (Generation 4) line of Glock pistols. The first in this series was the full-sized Glock 17 and Glock 22, chambered for the 9×19 mm Parabellum and .40 S&W cartridges, respectively. The GEN 4 G21 came along about 2013 and much as been written and videoed about the G21. So much so that it would be hard for me to expound any further on it, but expound I will do, because I have a feeling that at some point the G21 will receive the new G5 treatment, but only time will tell.

My first excursion with the G21 (and you thought that I was only a 1911 guy) was with the GEN 3; one of a bundle of Glock pistols that I purchased for a great price since my LGS was getting ready for the GEN 4 models and was clearing out their GEN 3s.

My liking of Glock pistols never really surfaced until I purchased the G43. Now, I am not a fan of the 9mm cartridge, but wouldn’t you know that I started appreciating Glock pistols, but not enough to place them above my beloved 1911 or even the Springfield XD and XDm.

More recently, I have come into possession of the Glock GEN5 G45 ( and realized, once I set my biases aside, what excellent firearms Glock pistols are.  That forced me to take a second look at the G21.

After pulling the GEN 3 G21 out of the safe, I came to the point that I wanted to take a closer look at the GEN 4 G21 and write an article about it like it was something new on the market. While I like being early for everything, I am certainly coming in late to the GEN 4 G21 party.

The G21, and its brethren the G41, G30, and G36 are not known to be the slimmest of pistols, but then not many staggered-magazine polymer pistols are. Companies like Springfield Armory have seemingly taken the high-capacity polymer-framed .45 ACP carrying pistols to a next level while adding a additional degree of safety that Glock pistols lack – a grip safety. And, I have to say that I certainty do like the XDm pistols and especially my XDm 4.5 and XDm 5.25 in .45 ACP, but still not to the point where I would carry it on a long-term basis. My confidence still lies in the 1911 and it still might take a 2×4 to change my mind. And, since the G21 has been compared to shooting a 2×4 with sights, if anything could steal me away from the 1911, the G21 would be it, but it would take a darn sure special pistol to do so.

The Gen 4 pistols were definite improvements over the GEN 3 family. The GEN 4 pistols display a modified rough-textured frame, grip checkering, and interchangeable back straps of different sizes.

The basic grip size of the fourth-generation Glock pistols is slightly smaller compared to the previous design. A tool is provided to remove the standard trigger housing pin and replace it with the longer cross pin needed to mount the medium or large back strap that will increase the trigger distance by 2 mm (0.079 in) or 4 mm (0.16 in). With the small back strap mounted, the grip is equivalent to the SF (Short Frame) G21. With the medium back strap installed, the grip size is identical to the third-generation pistols.

The magazine release catches are enlarged and reversible for left-handed use. To use the exchangeable magazine release feature, fourth-generation Glock magazines have a notch cut on both sides of the magazine body. Earlier versions of the magazines; however, will not lock into the Gen4 pistols if the user has moved the magazine release button to be operated by a left-handed user. Gen4 magazines will work in older models.

GEN 4 Glock pistols are fitted with a dual recoil spring assembly to help reduce perceived recoil and increase service life expectancy. The slide and barrel shelf have been resized, and the front portion of the polymer frame has been widened and internally enlarged to accommodate the dual recoil spring assembly. The trigger mechanism housing has also been modified to fit into the smaller-sized grip space.

The first modification after receiving the pistol was to, of course, change to the beavertail grip adapter. Fortunately, the pistol came with four grip adapters. And, just as fortunately, two were beaver-tails. A quick check for sizing and the large beaver-tail adapter was installed. You see, the GEN4 G21 comes with the SF (Short Frame) adapter installed. The trigger distance is 72.5 mm (2.85 inch). With the large beaver-tail adapter, the trigger reach increases by 16/100 of an inch, which increases the trigger reach to 3.01 inches.  For those with short fingers or thick hands, this would probably be too much distance. For me; however, it is near perfect. The girth of the grip is also increased slightly and does take some getting used to; especially, since I have operated a 1911 with large grips for a very long time. The grip diameter on my Rock Island Armory 1911 FS Tactical with Hogue Rubber Finger Groove Grips is 6” between the finger grooves. The Glock G21, with the large beaver-tail adapter, measure 6.5” in diameter. That may seem like quite a bit, but I feel that I have a better grip on the G21 than I do with the 1911, and that’s what matters.

My, oh what a difference! Although the reach to the trigger is increased, the pistol just melted in my hand and that beaver-tail really felt great on top of my hand. It felt like I was holding on to a unit rather than just a grip. The G21 and I were becoming one; singing of Kumbaya and the making of “Smores” were soon to follow, but I came up short of converting to veganism and wearing prayer beads.

The G45 has GNS (Glock Night Sights) and I have decided that I like the GNS. Getting a GEN 4 G21 with GNS; however, was going to be iffy. However, my LGS came through and found a GEN 4 G21 with GNS from one of his distributors that also cater to the Law Enforcement community. This particular G21 did have night sights and it was the only one available.  The Glock gods were smiling at me this day. Although a Glock can be ordered with GNS, there is a long wait from ordering to receiving the pistol (several weeks to several months from what a Glock representative told me when I inquired about the pistol). I had my GEN 4 G21 in a week with factory-installed GNS.

I will have to say that front night sight is much nicer than the standard Glock sight, and the front sight still looks like a speck on the deck of a aircraft carrier. The smaller front sight width just seems to make that slide width of 1.12 inches look even wider. But, the smaller night sights do help me focus my aim better than the standard Glock sights. I don’t even notice the slide width when I am engaging a target. The front night sight is a little longer than the standard sight, which shortens the rear to front sight distance a bit, but not enough to matter. The standard front sight radius is 172 mm (6.77 inch) while the GNS sights are 170 mm (6.69 inch).

The finger grooves on the grip are, of course, still there as with the Gen 3, but I am used to finger grooves and they don’t bother me. The 4.61-inch barrel is still the same as with previous versions of the G21, but is shorter than my 1911 EDC. The grip width is 1.34-inches. My usual EDC, the RIA 1911FS Tactical with Hogue finger-groove rubber grips, measures in at 1.285-inches in width. The length of the grip on the G21 is really no longer that my 1911 with a Wilson magazine with butt pad installed, which leads me into writing about concealing the beast in the near reading future.

The RTF (Rough Textured Frame) of the Gen 4 G21 has been modified and provides a little more grip to the grip than the GEN3 version, which is a plus in my book, as I find the GEN3 grip a little slippery. The modified RTF is still subtle, as compared to the Springfield XD pistols. The slide retains the Tenifer treatment as with Glock’s past. The barrel is still octagonal polygonal rifling, as with all 45 ACP and 45 GAP chambering.

The magazine capacity is still 13 cartridges in Free States, and the fully loaded G21 weighs in at 38.3 ounces (2.45 pounds) as compared to 45.92 ounces (2.87 pounds) of my all steel RIA 1911 FS Tactical. However, the G21 load is 13+1 cartridges and not 8+1 as with the RIA. A few more büllets never hurt anybody, unless they are coming in your direction. Basically, I am gaining a few more rounds of ammunition, but not increasing the overall weight that I am used to carrying. I can live with that.

Range Time

The GEN 4 G21 excels at putting large diameter projectile down range without skipping a beat.  Like my RIA 1911 FS Tactical, the G21 seems to like the Sig-Sauer V-Crown 230grain JHP ammunition and; therefore, is the chosen defensive load until something changes my mind.

Felt recoil is actually less than my RIA 1911 FS Tactical and is probably due to the polymer frame soaking some of it up. Yes, Martha, it does recoil more than a 9mm. That’s the nature of the beast! I may carry fewer cartridges than with a 9mm or .40 caliber, but they are big bullets and 13 of them punch a big hole in the center of the target just as well as a 9mm or .40 caliber – maybe even a bigger hole quicker.

The G21 is a very accurate pistol. With that 4.61-inch barrel, there is a long sight radius even with the shorter distance of the GNS, and a little increase in velocity helps to push that big projectile into doing what it is supposed to do – stop a threat.

The Glock Night Sights are not as big as the standard Glock sights, but being smaller, I find myself focusing more on the target. Personally, I find the standard Glock sights distracting.

Fifty rounds of Perfecta 230-grain FMJ and a magazine full of Sig-Sauer 230-grain V-Crown JHP was sent downrange without a murmur from the pistol. That made me a happy soul!

The trigger, while not as good as the one in the G45, is more than adequate. The trigger rolls past of the point of releasing the striker just fine.

Closing it Up!

Hah, you thought that I was referring to a summary! Nope, I am leaning to concealing a pistol like the Glock G21, which is no easy task for anyone to do with a pistol intended as a “duty” pistol. After all, there is the G30 and G36 that can be concealed easier than the G21. However, even with the full grip of the G21, the G21 can be concealed. Since I am a red-blooded, meat-eating American of medium proportion whose youthful figure has been lost, I can hide a Government Model 1911 relatively well. If you do your part as far as dress, belt, and holster you should be able to conceal the G21. Over the years I have adopted the “have one holster to carry many rather than many holsters to carry one” attitude. That attitude was shaped by my ‘Bucket” holster list.  That list is not holsters that I want before I die; it is a list of holsters that reside in storage buckets. Unfortunately, holsters still boil down to two types of holster, IWB and Shoulder.

The Galco Miami Classic 2 is my favorite for “wide-slide” Glock pistols like the G21 and especially when worn in cold weather when hip carry becomes cumbersome due to additional layers of outerwear. However, carrying the G21 in a shoulder holster during warm to hot weather may not work out so well, but I will have to wait until hot weather to determine that.

If you are of slender build because of your healthy lifestyle or high metabolism, you are going to think harder and be more creative in concealing a pistol like the G21. For my choice of holsters, the “Cumberland” from Simply Rugged Holsters won out over several others.  I have to note that the “Cuda” holster from Simply Rugged Holsters, which I had ordered for the Springfield XD/XDm 4.5 pistols, also holds the G21 quite well as the trigger guards are very similar. I just happened to have one on hand to try and will carry the G21 in it until the “Cumberland” arrives.

The “Cuda” (see my review @ was originally ordered with belt straps. While they are good, the holster has a tendency to slip a bit due to its very smooth-out texture. The “Cumberland (read my review @, on the other hand, which uses metal belt clips and a rough-out texture, and provides a much more stable platform – not that I would be break dancing like a certain FBI agent with a loaded and chambered firearm on my side ( You can’t fix stupid! The agent pled out to avoid incarceration (

Wrapping it Up!

Now, I am closing it down!

The Glock G21, regardless of generation, is a full-size duty pistol. It looks like one, it shoots like one; therefore, it must be one. If you feel like dressing up to one, you will be challenged in keeping it under wraps should you decide to conceal it.  Since my mental capacity exceeds the round count by a close margin, I feel comfortable with the G21 as my EDC or when defending the hacienda.

The G21, of course, shoots the venerable .45 ACP cartridge, and it does it quite well. Coupled with a suitable PCC in this caliber, I would say that you are adequately protected at medium and close distances.

The G21 has a full grip unlike its smaller brother the G30, and to which I have had to add a grip extensions to the magazines to get a proper grip on the thing. A larger grip means better control at the expense of concealment; however, the G21 can be effectively concealed if you do your part.

If you go with the G21, try and get one with the Glock Night Sights (GNS). They are well worth the small additional cost when light conditions are low. They are guaranteed for fifteen years and are backed by Glock. Of course, if a G21 cannot be found with night sights, the night sights of your choice can be ordered.

Have I finally turned a corner in recognizing Glock pistols for what they are? Yes, but I am not at the point where I need 12-steps to recover from an addiction to the 1911. The Glock G21 is an excellent tool. The 1911 is still a, well, do I need to say it?

If you are used to Glock pistols, there will be little transition to the G21. Coming from a more slender pistol, like a 1911, the G21 takes a little bit of getting used to, but the more I shoot it, the better I like it. But, has the Glock GEN4 G21 taken top spot in my carry rotation? Well, no it has not. But, it did result in researching another Glock product that is a serious contender as an EDC.

If the Glock G21 doesn’t fit your fancy due to its wide-body profile, what would you think of a Glock G41 with its slimmer profile and longer barrel” You can read about the Glock G41 @



About Taurian

Taurian is a U.S. Army veteran and former LEO and Defensive Tactics Instructor. Taurian also has over fifty years of experience as a Technical Writer and Training Program Developer. After leaving home at the age of ten without any shoes, Taurian continues on with many years devoted to the keeping and bearing of arms.

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