Glock 20 + Conversion Barrels = Ultimate Semi?

C

Cosmodragoon

New member
I don't have anything in .40 or .357 Sig right now and while combing the web for full-size and softer-recoiling options, I stumbled upon this idea. Supposedly, the 10mm Glock 20 can be changed to .40 or .357 Sig in seconds by just swapping barrels. Then I read that it doesn't stop there. I'm halfway between disbelief and disbelief that I've never heard about it before. If true, wouldn't this make the already respectable Glock 20 the ultimate all-caliber semi?

With a lot of threads all over the place on this subject, let's figure it all out in one place:

1. What calibers can a Glock 20 be with just a barrel swap?

2. Can you really use the Glock 20 10mm magazine for all of them? If not, which ones?

3. Which conversions require different springs or other changes?

4. How accurate, reliable, and durable are these conversions? Are there any you wouldn't trust?

5. With multiple companies making conversion barrels and some having dubious reviews, which are the best for each caliber? Does a good company offer a package deal for several calibers?

6. It appears that some companies offer custom fittings. How important or beneficial is that?

Any other comments?
 
the 10mm->40s&w or 357sig are perfectly reliable. I ran my Gen4 Glock 20 in 40s&w and it was my favorite gun for shooting 40 to date.
 
1. What calibers can a Glock 20 be with just a barrel swap?
40S&W, 357Sig, 9x25
even 9mm Luger wih the barrel and the spring exchange M/20 Conversion to 9mm LWD-20L9, need 11lb spring 6.02” $125
 
Lots of questions, and I have only a few answers.

You can shoot at least 10mm, 9x25, 357sig, 40S&W out of a g20. I am sure there are more, but these are the ones I have direct experience with.

I used my g20 10mm mags for all of them. No issues.

I used the same wolff aftermarket spring kit in all of them. The 357sig was getting a bit dodgy for the spring though. Probably too stiff.

I used KKM Barrels on mine. They worked fine and were no issue. I had to do some hand fitting though to get them in my g20. I use the KKM comped 10mm barrel still as my standard.

I can't answer the other questions on custom calibers or fittings. I did it myself.

Bottom line? I now just shoot 10mm in my g20.
9x25 was too abusive to my grip and was way too loud. It ws like holding a bat and hitting a brick wall with it.
40 short and weak was exactly that. Why waste a perfectly good 10mm bullet in a 40?
357 sig was interesting but I have a 229 sport that handles it better.
10mm KKM Comped 6" barrel was the best combination and all I shoot in the gun now.
 
Don't forget .38 Super; I see they make G20 barrels for that. And those .22 conversion units. With all the other chamberings, that makes for a very versatile gun. I have a LW extended .40 barrel for mine to accommodate a .45 suppressor I have, and to shoot cheaper .40, subsonic ammo when desired. That barrel shot a fist sized group at 25 yards the first time I shot it.:)
 
It is indeed very versatile, it and the G21, which is perhaps slightly more so than the G20 since the 21 can shoot 10mm and even better, .45 Super/460 Rowland.

I have a .40 S&W KKM barrel for my G20 and it shoots very well. The coolest part is that KKM .40 barrels have LONG throats on them, so I can load .40 S&W to long 10mm-like OAL (1.250"+) using 10mm data and have a 10mm from a cheaper, stronger .40 S&W case.

My complaint about the 20 is that it's pretty big. Not huge, but large enough that I prefer the smaller framed 9mm/357Sig/40S&W Glocks. They're simply thinner, lighter and carry better and to me, feel better in the hand.

Not to discredit the 10mm or the die hard 10mm enthusiasts, but really the .40 S&W (which can be converted to .357 Sig with a barrel swap or 9mm with a conversion barrel) can do pretty much anything the 10mm can. Sure the 10mm is a little faster, but all in all it's stuck using JHP bullets in which 99% of those are designed around the .40 S&W, not the 10mm.

If you load the .40 warm and the 10mm warm, nobody would be able to tell which is which in terms of killing ability. But, if you prefer the larger framed Glocks then the 10mm is a solid choice.
 
I think you are being just a little bit too imaginative here. the glock 20 is by no means the AR15 of the pistol world. the 10mm is essentially an enlongated 40 S&W so there would really be no difficulty swapping a 40 barrel for the conversion and using the same magazine. 357 sig is the same story, a 40 cal casing necked down to 9mm-ish diameter. I have personally seen a person feed a box of 9mm through a glock 22 accidentally. everything fired and no problems other than every single casing ruptured and accuracy was pathetic. given that knowledge, I see no reason why a 9mm conversion would not work.

I have personally picked up casings in my driveway for 380s... I don't own a 380 meaning that those were fed through my 9mms so in theory, you could drop a 380 barrel in the glock and still use the factory 10mm mags.

however that is where all easy swaps are exhausted. there are dozens of conversions to convert to 22lr but as I understand it you need to replace the entire slide assembly and the 10mm mags will definitely not work so you also need 22 magazines.

I think those 5 calibers are about all you'll ever get.
 
Except it remains a M20 Glock :rolleyes:
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WESHOOT2, was there a point here or is this just some general anti-Glock sentiment?

I'm hardly a Glock fan. I think Glocks are ugly. I prefer a hammer-fired pistol. This particular model is also pretty clunky. When it comes to a full-size and relatively soft-shooting pistol that could open up my ability to use at least three different novel calibers, what else would you recommend?
 
no knock on glock built one fine custom M20

Point: M20 is big to hold on to; gotta have the right mitts.



Too big for me. Nice and VERY expensive custom 10mm, had to sell it 'cause I didn't like it. Still didn't have the right mitts.

A large metal EAA Witness frame will take most everything, from 22LR to 45 ACP.
22LR
9x19
9x21
38 Super
40 S&W
10mm
45 ACP

And if you have the money, 9x25 Dillon, 357 SIG, 400 CorBon, and 41 AE.
 
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testify

I should add I own two 'small' and one 'large' metal Witnesses.
The two small were both originally bought in 9x19, and while one remains a dedicated (and custom) 9x19, the other 'small' frame does duty also in 9x21, 40 S&W, and 41 AE.

The 'large' frame was bought in 45 ACP, and back in the day I also ran it in 38 Super.
I often consider re-topping this with a 40 S&W longslide......


Or you could just start with their 10mm version and add tops as needed ;)
 
G20 is the AR-15 of the semi-auto world

my G20 SHTF kit is:
.22 upper, g21 upper, Guncrafter .50 upper and the full g20, with that and appropriate barrel (spring) swaps I can fire the following.
.22
9mm luger
9mm dillon
357 sig
.40
38 super
40 super
.45 acp
10mm
400 corbon
460 rowland
.50 beowulf

I am currently trying to add 380 to the list. My 12 gauge coach gun can fire 20 different calibers to include black powder using adapters.
 
I really don't understand the conversion bug. It doesn't necessarily save money. 1 gun with 2 barrels is not as flexible as 2 guns.

I think this itch is better scratched with a flexible cartridge, like 10mm, and handloading to create the ballistics you desire.

And all you're really getting a choice of is a range of medium power military handgun cartridges. It isn't like the G20 can cycle with everything from .32ACP to .44Mag.



This is obviously a human desire that goes further than just firearms. There's a lot of jewelry that you can swap the charms or whatever on. But my wife feels the same way I do about it: She'd rather have 2 bracelets than one bracelet and box full of parts.
 
If you read some of what is now called prepper books. If you had to evacuate or flee your home for a extended period of time. One or two firearms that could be converted to use several calibers gives you more options in an easier to transport package.

I don't know how handy it would be standing at the range and swapping barrels and slides.
 
I really don't understand the conversion bug. It doesn't necessarily save money. 1 gun with 2 barrels is not as flexible as 2 guns.
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I sorta agree. After paying for another barrel I'd just as likely pay for another gun. Especially as cheap as you can find used Glocks, around $350-$400 for most models.

I realize the thread is about 8 months old, but still relevant. FWIW, lots of folks simply shoot 40 S&W in their G-20 with no conversion. I've experimented with the concept enough to say it has worked 100% reliably for 100 rounds. Accuracy and POI is exactly the same as shooting 10mm loads, and they feed perfectly through the 10mm magazines. I'm sure they would do the same with a conversion barrel I'd use 40's in the 10mm again if given no other option other than throw rocks, but I'm not sure I'd recommend it for long term use. Although some have done so.
 
If you read some of what is now called prepper books. If you had to evacuate or flee your home for a extended period of time. One or two firearms that could be converted to use several calibers gives you more options in an easier to transport package.

I don't know how handy it would be standing at the range and swapping barrels and slides.
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More options for what?

The notion that anyone is going to find, give, or barter for high quality ammunition in a short or long term crisis is an unfounded fantasy.
 
Conversion gives one the ability to test out a caliber you would not normally fool with at a low cost.

Spend about $130-ish on a Lone Wolf barrel, go get some ammo, and you are in business.
Once you have tested out the new caliber, you decide if you want to buy a platform for it.
If not, you either sell the barrel on an auction site, and order the next caliber you want to try, OR
you keep it in case you run out of 10mm ammo...always good to have options!!

Bottom line, you get to experience MORE shooting fun!! :)


That being said, go get an extended length 9" barrel to play with...opens up even MORE options :cool:
 
I don't see how firing .40 through a Glock 20 is going to tell you anything about what it would be like to own a USP40 or G23.

Calibers are discussed sometimes like they each have their special characteristics, like a dog breed or something. But they are just different ways of getting a piece of lead up to muzzle velocity.

If you get a 180 grain bullet up to 950 fps second, you aren't going to be able to tell if you started with a 9x23, 10mm, .40 or .45 ACP casing. The recoil impulse and terminal ballistics inside 50 yards are going to be pretty much identical.
 
I really don't understand the conversion bug. It doesn't necessarily save money. 1 gun with 2 barrels is not as flexible as 2 guns.
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Thats been my experience, and with a couple of things, not just pistols.

I thought spare .40 barrels for my P226's and P229's would be a good thing. In the long run, I ended up with a spare barrel and a case of ammo for each, and both sat in the ammo locker gathering dust. A fair amount of money tied up and doing nothing, and still only one gun for each.

The only time it did pay off for me was when I did get a spare 9mm barrel for my Glock 31, mostly because the 357SIG it was chambered for, was beating the gun to death. That LWD 9mm conversion barrel stopped the wear, and also convinced me that 357SIG wasnt as big a deal as I thought, and saved me more money by getting out of it.

Actually, Obama, timing, and panic paid off well for me with the above. I sold off most of the cased ammo at twice what I paid for it, and the barrels went with it, and I didnt lose money there. Other than my HK's and a couple of Colts, making money, especially decent money, on guns and related stuff, has been a rarity.

While at first blush, having something that can be many things sounds like a good idea, reality is, you usually choose the one combo you like best, and the rest just sits on a shelf, never to be used again. Id rather have complete two guns that always are, that one that might could be eight, one at a time.
 
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