Whether you are looking to upgrade an existing GLOCK model or looking to go for something completely new, the GLOCK 22 should be at the top of your shortlist.
There is little to be gained by denying that the GLOCK 17 set the standard by which pretty much every GLOCK has been judged.
Thus the G22 is a tad longer, featuring a 7.95-inch overall length compared to the 17’s 7.32-inch overall length.
Likewise, you will have to heft about 3.5 more ounces.
The grip is also wider to accommodate the larger .40 S&W cartridge, but even with smallish hands that does not seem to present a problem for the majority of shooters.
However, it is because of this beefier design that you should favor the G22 over is 9mm brethren.
The beefier design allows the shooter to swap a specially designed 9mm barrel and GLOCK 17 magazine to shoot 9mm.
This is a great option when you want a little less recoil or cheaper practice ammunition.
However, that is not all. The GLOCK 22 is much, much more than a one-trick pony.
You can swap to a .357 SIG barrel and load the G22 .40 S&W magazines with a heavier load for increased stopping power!
That means for about an extra $250 or so, you can shoot three different calibers for increased stopping power or cheaper practice rounds as your mood suits.
If the .357 SIG feels a little too squirrely or you get a deal on some .40 S&W… you have options.
And let’s not forget a survival or SHTF scenario where you could be forced to scrounge for ammo (although given the pressure on the ammunition market over the past couple of years, many feel as though they are already there).
The difference is that you have to start with the beefier design, i.e. you cannot swap one of the 9mm variant (G17, G19 etc.) to shoot .40 S&W or .357 SIG.
GLOCK 22 Gen 4 – Evolution or Revolution?
The Gen 4 is best described as an evolution over the Gen 3 models, so you can decide for yourself whether or not saving a few extra dollars on a deal is worthwhile.
The main differences between the two include interchangeable backstraps (three sizes), reversible, enlarged magazine release, dual recoil spring assembly and rough-textured frame (RTF).
Gen 4 GLOCK pistols such as the G22 come standard with multiple backstraps, which allow the shooter to adjust the grip size of the frame between a small, medium and large.
The small is slightly smaller than the Gen 3 pistols. The medium and large increase the grip size by 2mm and 4mm respectively.
The medium should be the same size as the Gen 3 guns, so the option to go smaller or larger is significant from a dealer point of view, but aids in resale or comfort at the range if multiple family members will be shooting.
Enlarged, Reversible Magazine Release
This is an awesome upgrade for GLOCK that GLOCK shooters had be clamoring about for some time.
It also eliminates one more common after-market upgrade.
The magazine release can be set up on the left or right side of the gun and the enlarged size makes it easier to engage when under pressure or while wearing gloves.
Also worthy of mentioning, during the 1,000 rounds and several dry fire sessions, I have never once experienced any unintended magazine drops due to the increased size.
Dual Recoil Spring Assembly
The dual recoil spring assembly looks similar to a GLOCK 26 or 27 assembly (but longer).
So far, the reports have been positive and many people have retrofitted the assembly to earlier generation pistols.
Whether or not you will be able to feel the difference when shooting is debatable, but reliability will be enhanced regardless.
If lighter recoil is something you are looking for, you can opt for a machined slide such as the one I recently received from J&L Gunsmithing.
The machining also allows the shooter better hand purchase (grip) when racking the slide.
Rough Textured Frame (RTF)
The RTF caused quite a stir among some shooters when it was first introduced, they felt it was too rough.
The RTF texture is fairly aggressive, but provides a positive grip.
The enhanced texture is certainly welcomed if you ever have to shoot in the rain or in when the mercury rises and you start to sweat.
For those who think it is too rough, my first recommendation would calluses earn from a bit of manual labor.
Alternately, you could knock down the edges with a light sanding or opt for a custom stippling from a reputable gunsmith.
In fact, for a few dollars, you can buy a soldering gun and stipple it yourself, but be sure to practice on another polymer or plastic product first.
Final Thoughts: GLOCK 22
For the money, it is hard to beat a GLOCK. It has a hard-earned reputation for reliability and accuracy.
That said, I could find no advantage to buying a 9mm variant. It simply limits your options. Instead, look to a .40 S&W model such as the G22.
That way, you have the option to swap barrels and shoot the .357 SIG or with a new barrel and magazine you will be set up for 9mm.
While customizing a gun is not for everyone, GLOCKs can certainly benefit for a few upgrades.
The author’s latest gun to be built by J&L Gunsmithing includes a short-reset trigger, extended rear sight to increase the sight length and increase accuracy potential.
The steel front J-hook sight allows the slide to manipulated one-handed by hooking it on a pocket or vest should the shooter become injured.
The machined slide lightens the gun overall, reduces felt recoil and muzzle flip for faster follow-up shots.
Rounding out the build, the GLOCK 22 was Cerakoted for a custom look and enhanced protection from the elements.
Does the GLOCK 22 top your list? Share your favorites in the comment section below!
I know all that works…
and good to…
I had a G22 40S&W and used to shoot 9mm and 357sig. through it all the time..
I ended up selling my G22 however I kept the 9mm and 357sig barrels and bought a P80 80% frame in FDE and plan on building it into a G22 variant so I can use my extra barrels in it…
I’ve got a bunch of 357sig. Ammo and no way to shoot it…
But I will…
I went with the G4/23. I also added a .22 conversion to the mix. I now have what I consider the ultimate handgun package 4 calibers in one. The three replacement barrels are all threaded, as each of those calibers has a subsonic version available. Plus they are all threaded the same. With a little tinkering, I found a discreet case that holds it all. Now if only someone made a decent carbine conversion for the 23.
I’m looking for a thumb safety. Got one of those?
Matt, not a thumb safety, but a very nice trigger with a button safety. Works really well.
Did you have to make any internal modifications such as changing the ejector?
I did not. The 9mm functions just fine. The .357 SIG is a nit hard on the gun and if I was going to shoot it a lot, I would opt for a stronger spring. ~Dave Dolbee
Would the conversion work on a G22 Gen3 or it’s only for only Gen4 Glocks?
I have a Gen 3 – nor problems at all. ~Dave Dolbee
i do not remember seeing conversion barrels for the 10 mm. but i was not looking for one for my 20 either. go to the places that sell conversion barrels and see if there are any. i have bought conversion barrels from 2 different organizations.
“Thus the G22 is a tad longer featuring a 7.95 overall length compared to the 17’s 7.32 overall length”
Not sure where you’re getting this. I own both a Glock 22 Gen 4 and a Glock 17 Gen 4, and they are identical in every dimension except width, where the 22 is slightly wider.
While I didn’t drag out both of my full-sized G17 or G22 pistols to measure with my calibrated caliper or micrometers, I had the same impression with only a cursory glance but admit I didn’t look too closely at the dimensions of the 9mm or .40 S&W O.D. for the barrels or the I.D. of the slide holes for their respective barrels.
That said, there is a gun show coming up next weekend and if someone has a Lone Wolf barrel that is a truly drop-in fit for my G22 in 9mm and they don’t want an arm and a leg and my left nut for one I might kinda, sorta, mebbe, gonna get me one.
No need for mags as I have a fair number, but if someone has FACTORY Glock mags for the G17 at a REASONABLE price, why not? 😉
As for the .357 Sig, those are pretty much as scarce as Hens teeth in these parts for reasons unknown to me. Several shooting Buds claim to have HAD them but no longer. To me, that speaks volumes.
Not to shortchange the round, I mean how CAN you when you have a shootin’ iron with very nearly the same ballistics as the wheel gun round in a smaller platform with far more rounds available in the event of a protracted social engagement.
It just never caught on with the shooting public and I have to wonder if it suffered the same situation as the 10mm in full powered loads; too much of a good thing for the “average” shooter at too high a price (the cause of which I surmise was/is market driven…not enough sales for amortization of the equipment to eventually allow lower overall pricing, but what do I know, right? 😉 ).
Additionally, you just about cannot swing a cat by its tail in most places without hitting an ammo supply in either the 9 or .40 but you’d need to launch a MIRV Nuke with a CEP of 50 klicks and STILL might not find .357 Sig ammo. That’s my story and I’m sticking with it so no plans to gear up for that round, Nosiree.
Again, just my musings and observations.
Thanks for your thoughts and observations.
While being an older article and being out for a couple of years now, I’ve read it several times, each time I’m able to glean a bit more information or see aomething I may have previously missed.
That said, I’m curious about a couple of things regarding the interchangeable barrels discussed.
First off, are these barrels all “Factory Glock” barrels or aftermarket?
Secondly, is it a requirement to trade out the recoil spring assembly to a caliber-specific assembly each time a barrel swap is done?
Third, are the barrels all of the same “rifling” configuration as a factory barrel or the more conventional lands and grooves which would allow the firing of lead projectiles?
Fourth, considering the trajectory of each caliber projectile for a given bullet weight, are the factory sights on the G22 regulated such that the shooter will still be on target with either the 9mm or the .357 Sig round?
Granted, in a combat environment or SD shooting situation you ought not be engaging an aggressor at rifle distances but, hey, SH*T “DOES” happen and only accuracy and projo’s on target are what count.
Lastly, what and from whom should one order the appropriate barrels from to ensure a “drop-in” component (be it just a barrel and/or recoil spring assembly) and rest assured the O.D. is appropriate for the G22 slide and, in general, what would one be expected to pay for a set of barrels in 9mm and .357 Sig?
Heck, for that matter I would propose buying an aftermarket barrel in .40 S&W with typical lands and groves that would allow the shooter to fire lead projectiles, too. After all we’re talking about a SHTF situation and one “might” have to resort to casting and loading lead bullets if and when the stockpiles of jacketed or plated bullets are exhausted or become unavailable.
Thanks to any and everyone who can respond with factual information.
PS, as the owner of several Glock pistols in various calibers (except the .357 Sig) I’ve never contemplated the switch-barrel option much before now, but when it comes down to it, I can see the value of owning just a small number of spare components to reconfigure a single pistol platform to allow versatility. Especially if that means the difference between being able to actually USE a handgun in the APPROPRIATE caliber as opposed to having to carry multiple handguns or, THE HORROR!, of having one caliber, running out of ammo for it then coming upon a number of OTHER caliber cartridges but not being able to use them because of dimension issues.
Certainly nothing to sneeze at, eh?
Thanks again for allowing me to drone on and on.
good questions, and i have not tried my barrels for functioning. not sure when i will get out to try them either. i have been busy working on my parents house. you have to have the right mag. if you go from 40 down to nine you need 9 mags. the 357 mags will will work with 40 mags. i have assumed that the recoil spring will work, but since you are going down in caliber i suppose it could be to stiff. that might be over come by loading the nines hotter, of course staying within safe limits. wish i had got out and tried them. heck i have not found the time to reload some lead bullets either.so i guess i am not much of a help. i suppose after trying it should i need a lighter recoil spring i will get them. i have not set up to cast yet but it is in my plans and i have a lot of lead bullets from before everything got so expensive. i certainly hope the prices will come down, they appear to be starting to. it does amaze me that all of a sudden the reloading supplies got so expensive. i cannot imagine that that many people started reloading. maybe everyone saw a chance for more profits, all those companies certainly have been doing well since obummer started his crap or should i say democrap. i do not have a 22 or a 17 they are just to big for what i want.
the barrels are about $150 to $200, but watch for sales i got most of mine for close to $100, if i remember right it was around 115 to 120. i have shot lead bullets in my glocks and quit a few, but i i learn more i decided it was better to go with land and grove barrels.
A question instead of a comment. I have a G27 if I buy a wolf barrel in 9mm will I be able to shoot 9mm without changing any thing else
i am not sure but i have bought a 9mm for my 27 but i believe where it goes through the slide the diameter of just the 9mm barrel would be to small. i bought the barrel for a 27 in 9mm, i if what i said is right the outside diameter of the 9mm for the 27 is larger then the barrel for the 26. you will also be required to buy 9 mm mags to run with it. those are all you need.
i do have a lot of questions myself. first i want to say when he said he reduced the weight of the slide and that reduced the recoil, i believe that is wrong. the recoil force is a function of weight and i think velocity squared. reducing the weight would make it have more recoil. if i am worng i hope someone will help me understand it.
i have both the 19 and 23 and the 26 and the 27. it did surprise me that the 40 was built stronger i can not tell the difference when shooting them side by side. i also have the 33 which is the 357 sig. if there is a barrel for changing the 40 into a 357 sig i will probably get one for both the 23 and the 27.
the reason i got extra barrels is so i do not have to worry about shooting lead bullets in the guns i have even got a 9mm barrel for my nine glocks because of the lead. i have not started casting my own bullets but i think i will get into it just to make sure the government has less control over me.
so when buying a conversion barrel buy it for the gun you are converting, not just a 9 mm barrel. my question that i have and would like an answer to is buying a barrel for the bigger glocks bigger in dimensions for the lock up? in other words could i buy a conversion barrel for a 22 and put it in a 23 or 27? it might be nice to have a longer barrel and get a little more power.
Yes, a conversion barrel such as a Lone Wolf barrel change is all that is required. It will even use the same recoil spring. It is that simple… Well, don’t forget you’ll also need to change to a 9mm magazine as well.
All Glock magazines are interchangeable and fit the width, but as you go up in capacity the magazines get longer. It would look silly to have a long magazine from say a G17 sticking out of your subcompact – but it could be done.
Instead, for your subcompact you would want to buy a G26 magazine so it matches the length of your magazine well. A G26 magazine is the 9mm subcompact length-equivalent of your original G27 magazine – but will give you one extra round since 9mm is smaller than .40 caliber.
I hope this answered your question.
yes it does look funny with the larger mags, but i really like the idea of more rounds. you can carry it with the proper mag and if you need to do a reload, looks are not going to matter much and i have tried the bigger mags and they work great. in fact for a 27 and i think the 357 sig is 33 not sure, it even gives i little more grip surface for your hand. i even bought those large capacity mags so you have 33 9’s and i do not remember the capacity for the 40. i think that is a great selling point and you can not have enough ammo but you can’t have to much. looks aren’t everything.
I’ll take my “just a Glock” 19 9mm pistol up against anything out there for daily carry. It’s the best compromise considering all the variables. Given the current state of the quality and potency of serious self defense ammunition available in 9mm stopping power is not an issue. Given that I can get well over 400 ftlbs of energy out of a round like the Cor-Bon 115gr JHP +P there is really no need for anything more. Given the capacity of the G19 I can feel comfortable in my ability to engage in a slightly more extended engagement than anyone with a 1911. Recoil is mild and with my XS Big Dot tritium night sights accuracy is outstanding within almost any defensive range. Magazine selection allows me to carry anywhere from 10 to 100 rounds depending on my choice. The 15 round standard magazines are almost indestructible as is the Glock pistol itself. It will run and run and run, eats anything I want to feed it (aside from cast lead) very very reliably.
For me at least the Glock 19 is a “to hell and back” level firearm. I trust it with my life and the with the lives of my loved ones. There can be no higher endorsement of my faith in the G19 than that.
i have had great result and trust my life to glocks, but i did have a 10mm, i think it is the glock 20 develop a crack in the upper part of the mag. i sent it back to glock and to their credit they replaced it. other then that i have never had a problem with any glock or mags i have owned even though i still am not a plastic guy. i did buy that 20 in the early 90’s. i understand what you are saying and everyone, most everyone agrees with you on the nine. i do not. while i would carry my 9, my choice was the 40 but after i got my 357 sig that is my go to until i do not have it. so i carry a nine mm bullet but i believe it is the speed which is the most import thing, velocity squared. the 357 mag was and i think it still is the best one shot stop with a fast 125 gr. bullet. i think the 357 sig is really close to that and that is why i stopped carrying the 40sw.
Looked into it once. By the time you buy every thing needed your far north of $800. And. Then you figure in carting all the pieces around and break down time. What a hassle. And when was the last time you really shot 357 sig. Save your money and buy a good 9 mm for practice and 45 for stopping power and call it a day. I know Glock lovers can be haters so I will not endorse any brands.
actually if you shop and wait for sales you can get a conversion barrel for a little over $100.. normally it can be done for 150 to 200. of course you also have to get mags for what you are converting. it allows me to shoot my reloaded lead bullets. i have shot them with the glock barrel but they say you can blow up your gun. i guess the poly rifling can lead up where as the cut groves allow for leading without pressure build up.
I have several Glock 10mm pistols and successfully fire 40 S&W with no changes to the weapon needed and still use the 10mm magazine.
first let me say i am not expert. David, i think you are making a big mistake. the mags might work, but i think one designed for the 40 might be better but i could be wrong and it might not fit in the mag well as well.
i am pretty sure the both rounds are stopped by the front edge of the case, the mouth. the difference in length might mean the 40 could slide in to far to even fire by the firing pin. i do not think that it is dangerous, unless it was for defense and the gun didn’t function. you then might have nothing but a club to use until you can get that round out.
I own a G19, G22 and a G32. They shoot and function perfectly, and are accurate. I also have conversion barrels for the G32 and G 22. That should tell you how highly I regard Glock pistols. But I wouldn’t pick a Glock for daily carry. I was trained on a 1911 back in the day and have carried one ever since, and I’m in my 60’s. I am accustomed to a slide safety/hammer safety, grip safety and half cock. All external safeties. I’m also accustomed to carrying in Condition 1, 2 or 3. Glocks on the other hand have only the trigger safety and an internal safety, no manual safety. Also moving the slide just a bit, 3/8 inch, will arm the striker which is also a con for me. If you grew up on striker fired polymers, it is all natural for you so its a great daily carry. I’ve been a smith and an FFL for a few decades now. I do some work for the local LE. They tell me about the tactical advantages of a Glock and also how many negligent discharges there are every year, normally they never get any attention. Most of them wouldn’t have happened with the safety features of a 1911. Again, I not critical of Glock, they are outstanding pistols. I’m saying that for me, its not a daily carry pistol.
i certainly would not tell anyone what to do and everyone has the right to do what they want. if i ever have to pull my gun i want it ready to go with only a trigger pull. i know if i have one in the chamber it is ready to go. if it is in a holster that covers the trigger it cannot go off until i remove it from the holster. i certainly myself want a fast bullet, as fast as i can get. it was the speed that made the 357 mag king of the one shot stops at i think 97%. the 45 acp had just over 90%. everyone says the nine is close, if i need it i want the best not close.
i certainly would not change my carry 1, 2, or 3. i would not want my muscle memory trying to decide which carry i have put it into today. i have seen videos of a store clerk who was killed along with his son. the clerk was trying to rack the slide for quite a while while he was being shot. that adrenaline rush can make you loose fine motor skills. i do not want to try and rack a slide and in the excitement follow the slide forward and cause a hangup. i want my gun ready to go and i trust my glock completely and even though they are reliable, who knows what may happen and i know i have at least one shot for sure. we all have to decide what we are going to do. i only want to pull the trigger when i draw.
Its still “just” a glock
i know, that is why i carry it.
I went this route with my G-23 and am quite pleased with the results…3 clalibers for the cost of just over 1 1/2 pistols…works for me!
i have not tried my barrels but being able to shoot lead bullets is a big PLUS. besides the change of calibers.i still would like to know if the 22, 23, and 27 barrels will interchange. i guess when i have some time i could try my longer 23 barrels in the 27. i think being able to have a little longer barrel would have advantages without much change in concealment. more velocity.
Could you get a Glock 20 (10mm) and then be able to shoot 10mm in addition to 357 SIG, 40 S&W, and 9mm?
After reading this article I’m wondering how the Glock 17 and 22 are different. Owning both i don’t see how ones longer or even thicker then the other. maybe i misread your article but i doubt it after rereading it.
The G17 is designed for 9mm; the slide is not designed to accept a barrel with an outer diameter large enough to fire a .40 S&W. On the other hand, the G22 is designed for the .40 S&W therefore, it will accept a 9mm barrel with thicker walls to bring the outer diameter to the same as a .40 S&W. ~Dave Dolbee
While I whole heartedly agree that the .40S&W Glock series of pistols are likely the best value going in hanguns, I had one issue with this article. My question for the author is regarding the statements made about the machined slide. You state that the machined slide both lightens the pistol and reduces felt recoil. How is this physically possible? In my experience adding weight is what reduces recoil and aids in better control for faster following shots and reducing weight results in an increase in felt recoil. Perhaps I’ve missed or misread something along the way but from my understanding of physics I simply don’t see how lowering the weight of the slide could possibly reduce the recoil. If you could explain and cite your source for that information it would be greatly appreciated. Thank you.
True according to physics lighter mass weight would equate to more recoil. For instance, I learned to shoot on a Colt .38 and a S&W .38. The Colt was heavier, but had less felt recoil. Shooting the two Glock 22s one after the other, the one with the machining exhibits less muzzle flip and feels like it has less recoil although I have no scientific data to back it up – just a handful of shooters, new and experienced. The main purpose is of course better hand purchase should your hand be wet, slippery or heaven forbid, bloody. ~Dave Dolbee
I have a G 27 is there a conversion barrel in a smaller cal. for training?
Rob, I fail to see how that is an advantage. Isn’t that true of every gun?
I own a Glock 22 gen 3 and couldn’t be happier with it. The gen 3’s grip fit me excellently so I saw no need to upgrade to the gen 4. I have a 9mm conversion barrel and the 357Sig is on my Christmas list. It is extremely accurate and precise (I cheated and added a Lasermax green guide rod laser. Though the racking is a bit stiff, it is dead on at 50 yards. Recoil is light with both barrels and the pistol drops right back down to target.
Keep it up Glock the model 22 is a big winner. Why else would it be preferred by law enforcement.
It sounds like you stole my gun.
I have the exact same setup on a G22 Gen 3
I have the 9mm and 357 Sig conversion barrels and mags PLUS an Advantage Arms .22 lr conversion kit. In seconds I can switch to 4 different calibers and they are all very accurate.
Can you tell me what other gun will have this versiatility??
Glock is an excellent choice in any model or cailber.
BUURGA, just exactly what is your point. You seem to be telling us not to carry. Then you talk about a Glock being too expensive. Then you say the pigs will take your gun away for evidence. What gun are you talking about carrying. They’ll take away any gun, not just a Glock.
Pigs, huh? Sounds like you have Daddy issues. I’ll bet you $100 that when you are pulled over, you do not address them as such. But you are brave behind a key board. Ross, no one is taking your guns, if you are legally authorized to own one. Just like no one is kicking in doors just because you want to fire up a joint in your own home. Paranoia and urban legends bro. Get a grip.
The police confiscated every gun, knife, and nail clippers in every vehicle (motorcycles AND cars) when they went wild and killed 7 people. and arrested family folks who were out for a Sunday lunch. This happened not too long ago in Waco, Texas. It’s a Branch Davidian Massacre all over again. Many family men are still in jail on a $ 1MILLION bond. Meanwhile they lost their jobs and their families are seeking shelters for homeless families.
I can understand why folks refer to certain police departments as pigs.
Not sure were you got the dimensions from but the Glock 17 and 22 are the same size, magazines are interchangeable too.
Glocks are terrific pistols well deserving of their rep. HOWEVER, anyone who carries such an expensive pistol for CCW is wasting their money. The combat life of a gun in a self-defense situation is 1 -2 mags. After that it is taken into evidence and may be weeks or months before it is returned. It there’ a a fatality you will likely not ever see it again. Get a Glock and use it at the range to keep your skills up.
What a ridiculous statement BUURGA. You obviously do not have a clue.
I’d at least be alive while waiting to get my 22 back if i did ever have to use it.carry mine everywhere.you sound like a real fool.and no im not a cop.shoot him with you 2 5.or your nice lorcin.if it works or you can hit what your shooting at.sad.
Go ahead and tell us how many folks you shot, BUURGA.
Isn’t the Glock 22 a compact version of the Glock 20 which does all the caliber changes as well?
No. They do offer conversion barrels but its not as easily done as with the 22 to 357/9
Thanks, Joe, I didn’t know the 20 was more difficult, but I will get the 20 anyway because I want the 10 and I can also use the .40 and the .357
Then there’s the Glock 29 for a smaller 10mm with interchangeable bbls.
Umm… Its just as easy with a G20 10mm to covert to 40/357 and even 9×25 Dillon – I’ve done it – In some cases one might need to change to a lighter recoil spring, but I did not. I just dropped in a conversion barrel and it just worked.
You can shoot .40 out of a 10mm glock with no modification using the stock 10mm magazines. It is the exact same diameter bullets. The .40 caliber shell is just a bit shorter than the 10 millimeter shell. Just do a google search and you will see a lot of of people do it with lots of success. As always it’s not something glock will say is ok. However chamber pressure on .40 is lower than on 10mm so you should very safe trying it to see if it works for you.
I use a gen 2 G22 with a Storm Lake 9mm conversion barrel for IDPA. I like the extra weight of the barrel for follow up shots. Love it!
How does the Storm Lake bbl give you extra weight. I was thinking of getting the Lone Wolf extended bbl. for carry in the mountains. I wonder how the 10mm compares to the .44 mag?
The conversion barrels are heavier because they have to keep the same outside diameter for the barrel to work in the slide but have a smaller caliber so the bore is smaller. This makes the barrel walls thicker thus providing the extra weight.
The thicker/heavier does the same as a tungsten guiderod – add weight to the barrel end to tame recoil.
The 10mm would more closely approximate a heavy .357 Magnum (+P maybe) loading power wise in most loadings, more so than it would the .44 Mag, albeit with a slightly larger entry hole. It does make for the best hunting round fireable from a modern, affordable, semi-automatic pistol. Though I trust in the power of the 10mm it is simply too expensive to practice with adequately, IMHO. That being said I must say that the ability of so many of the Glock Family pistols to wear so many different barrels and/or magazines provides a superb value for anyone in the market for a truly versatile handgun. The 20 can easily be converted to .45acp as they use the same frame and slide configuration. That makes for a two/fer similar to the .40/9mm capability of the 22 & 23 for those who enjoy the larger calibers.
The 10mm in it’s original factory loadings were closer to a .41 Magnum. Due to Bill Clinton insisting on more female FCI agents, they had to lower the upper body strength requirements to allow the women to pass the school. They also, the vast majority anyway, could not handle a full house factory 10mm loading.
Miami Vice had some realistic sounding blanks for Don Johnson’s Bren 10