Glock 20. How many calibers

40 sw ,45 acp, 45 super, 40 super are the ones I know of offhand. A lot of people shoot 40 S&W in the stock 10mm barrel.

Since it is a 10mm, it will work with anything that the 10mm breech face will accept. That includes 40 S&W, 357 Sig, 9X25 Dillon.

There have been other caliber conversion barrels, such as the 9mm Luger and 38 Super. They worked ok - they extracted fine even with the 10mm Breech face and extractor, but feeding has been inconsistent from the 10mm magazines even when modified. One was even converted to 9X23 Winchester, but the feeding problem kept it from running 100%.
https://www.shootingtimes.com/editorial/glock-conversion-9x23-winchester/99520

One person used a Glock 10mm for the 357 Ring of Fire, which is a cut down 9mm Win mag round.
https://www.shootingillustrated.com/articles/2018/9/30/review-357-ring-of-fire/

I don't know if it will handle 45 ACP without changing the slide to get the 45 ACP breech face.

I'm thinking you can get more options with the G21 in 45 ACP with just a barrel and mag change.

If you were to swap uppers completely for a 45 upper then you can get really solid money for your used upper. I’m looking around now to figure out pricing because I have a g20 frame that needs to grow some other parts.

PapaG said:

People actually shoot 40 with no mods?

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Never shoot non standard ammo and if you do always at your own risk and it probably isn't smart.

But yes many have and do including myself for many thousand rounds in multiple 10mms. Google it and see the reason it's not as stupid as it sounds then decide for yourself.

Lone Wolf used to sell more conversion barrels I think. Now, I only see a .40 conversion barrel with them for the 20 at $140. I'm sure looking around you can find more options.

ric jackson said:

40 sw ,45 acp, 45 super, 40 super are the ones I know of offhand. A lot of people shoot 40 S&W in the stock 10mm barrel.

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Can’t shoot .45 or .45 based wildcats out of a 10mm slide far as I know.

I believe I was thinking of going from G21 to G 20 .

PapaG said:

Headspace on case mouth.

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Measure from slide face to shoulder in the barrel on most duty semi-autos. Then check that against trim-to length.

I have ran several hundred rounds of 40 S&W ... in my 29 & 20 with stock 10mm barrels ..... Ran 100% .. no problems ... Nuthing but fun

I

crestoncowboy said:

Never shoot non standard ammo and if you do always at your own risk and it probably isn't smart.

But yes many have and do including myself for many thousand rounds in multiple 10mms. Google it and see the reason it's not as stupid as it sounds then decide for yourself.

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I have heard that Glocks have no real issues doing this (and the High Point Carbine as well I think), but its works fine in other 10mm's as well?

I just bought a g20 lower and am figuring out the direction to go. There is a video that shows 11 caliber options for the large frame pistols, 9mm being the smallest and 460 Rowland being the most potent. The ones I remember...
9mm
9x25 Dillon
38 super
10mm
45acp
45 GAP
460 Rowland
400 Corbon
22lr via a junky looking conversion kit.

and 357 Sig. I have a Lonewolf conversion bbl for G20.

BlueHeelerFl said:

but its works fine in other 10mm's as well?

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I've not had it fail in anything but a 6 inch glock with a kkm match barrel running a very heavy recoil spring. And it was obvious that it was just oversprung for the ammo. That said, I dont do it in my 1911s because parts are higher and not as "drop in" but I have tried it to see and it was fine for a few mags . A Glock extractor and spring is 10-15 bucks and will work with no tuning. And you may be putting more stress on the extractor so you may cause it to fail earlier than the thousands of rounds it would have lasted.

Again it could blow up and be a bad idea. I'm not telling anyone it's safe. Just that I have not had an issue. But like I said, load a dummy 10mm round with the brass trimmed to the spec. Then stick it in your 10mm chamber and see if you are really spacing off the mouth. I havent seen one that was.

d'zaster said:

and 357 Sig. I have a Lonewolf conversion bbl for G20.

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I would like to find a 357 Sig for my G20. All I have for mine is the original 10mm and a Bar-Sto 9X25 conversion.
I got so tired of looking (it didn't take long!) for the 357 Sig barrel, I just bought a G35 with the 357 Sig conversion barrel included. I still can't shoot 357 out of my G20, but it really flies out of my 35.

I just bought a g20 lower and am figuring out the direction to go. There is a video that shows 11 caliber options for the large frame pistols, 9mm being the smallest and 460 Rowland being the most potent. The ones I remember...
9mm
9x25 Dillon
38 super
10mm
45acp
45 GAP
460 Rowland
400 Corbon
22lr via a junky looking conversion kit.

crestoncowboy said:

Never shoot non standard ammo and if you do always at your own risk and it probably isn't smart.

But yes many have and do including myself for many thousand rounds in multiple 10mms. Google it and see the reason it's not as stupid as it sounds then decide for yourself.

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I shoot 40 S&W frequently in my G20. They always feed, fire and eject without any problems.\
I know several others that do this also.

jmohme said:

I shoot 40 S&W frequently in my G20.

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I do too a few k a year in my 29 and 20 and I've tried it my other 10s just to see. I have since I was in my 20s and a competitor showed me that his 40 he was using was actually a stock 10mm. He shot 10s of thousands of rounds a year. Still never a bad idea to tell people that's its usually not a bright idea. Then let them decide for themselves

G21 has more options, with G20 you're limited to .40, 357 sig, 9x25 and 10mm. I'd recommend a conversion barrel for .40 simply because while you can shoot .40 in a 10mm, it's only held in place by the extractor because it's not headspacing correctly. Sure it may work but it's causing the extractor to do something it was never intended to do.

PapaG said:

Solved my problem today. Since I hunt with big revolvers anyway, I swapped the 20 for a 43 for edc. Thanks for all the info. I'll pass on trying ammo in firearms not chambered for it.

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Oh no! The g20 is an awesome firearm, but it isn't for everyone . I have heard people using 45 cap barrels but I haven't seen a 45 barrel that fits through the 10mm barrel hole and if it did it would need to be quite thin. 9x25 Dillon is awesome but if you have a 10mm I don't see a need. I've been a 45 guy (acp & colt) for as long as I've been shooting but the 10mm has become my favorite bottom feeder ever (g20). While I prefer big revolvers for powerful loads , the 10mm is substantial and very good for the limitations of the guns designed for it.
Enjoy your new g43 and good luck to you.