Glock 20 conversion to .40 and 357sig. Mag questions

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Ocraknife

New member
I have a Glock 20 with a lone wolf .40 conversion barrel and one in .357sig. I expect the stock mags will with work fine with .40 cartridges but would in need different mags or followers to run .357sig?
 
And it's more expensive than 357sig.....brass wise at least. But it's fun.


Some dummy rounds I made while tweaking my set up.



 
It's not likely you'll ever see it on a shelf anywhere. It's a boutique caliber that reloaders tinker with.

Underwood, Double Tap, and a few others sell it, but that's about it
 
I would suspect that the factory 10 mm mags are good to go. The HK MP-5 in 10 mm used the same magazines as the 40 S&W caliber MP-5.
 
I bet 9x25 dillon (spelling?) would be an awesome chambering for a woods gun. With good ammo it bet it would be like the hottest .357 mag loads.

I can order a barrel for the Glock 20 for about $100, should I do it? What about magazines? Is there a magazine I can buy that will work our should I plan to modify a Glock 20 mag?
 
Hmmmm!

I wouldn't think so......if you reload, you could even load the .40's a tad long to make up some of the difference in C.O.A.L., heck, maybe most of it, the .40/180 is a long slug. Those big frame Glock's & mags only come in two flavors.... .45acp and 10mm, I'm not aware of any other followers that would fit the mag box.
 
The .357 sig uses a .40 case necked down so if the gun will feed .40 it SHOULD feed .357sig. Make sure you thoroughly test this before depending on the gun for anything. I don't know why you would want a .357 sig barrel as the 10mm does everything the sig does plus some. I just watched a video today by 22plinkster, and a 140gr xtreme penetrator at about 1550fps blasted clean through a sheet of ballistic glass. A standard armscor 189gr load didn't even make it half way through but the high vel 140gr drilled through about 2" of the stuff. Also watched a video of a 140gr xtreme penetrator going through a level 2 Kevlar vest, about 8inches of wet sand, then 2 full gallon water jugs.

With the 10mm you can go light and fast for barrier penetration like the .357sig or heavy and hard (200-230gr) for meat/organism penetration
 
The 10mm is 1.260" OAL, .45acp is 1.275" OAL, where the 40S&W and .357SIG are 1.140" OAL. The 40S&W and .357SIG mag bodies are the same, the followers have different part numbers, but each will feed fine will either type follower. Seems like to run a .357SIG in a G20 magazine you would have to use a .12" spacer in the back of mag to make up the OAL.
 
I bought the .357sig barrel on a whim. I bought the .40 barrel because the ammo is so much less expensive than 10mm so I thought it would be a good way to practice cheaply.
 
Range report. Both barrels worked perfectly. Both .357sig and .40 fed and ejected flawlessly with the stock 10mm mags.

It was fun to shoot the .357sig for some reason. It had a very different recoil than the .40 though it seemed to me to be louder.

I shot .40s in the replacement barrel every bit as accurately as I do the 10mm in the stock barrel.

I think I need to start pricing 9x25 ammo next then get a reloading station :D
 
I bet 9x25 dillon (spelling?) would be an awesome chambering for a woods gun. With good ammo it bet it would be like the hottest .357 mag loads.
Click to expand...

The 9x25 Dillon is what finally put a pair of hairy nads on the .355/9mm projectile, and it's a round you can actually shoot in your big-boy (10mm) Glock or a 1911, not some whittled-down twad gun.

And as you've discovered, the stock Glock 10mm mags will feed these derivative cartridges just fine - .40, .357Sig, & 9x25. But that isn't new news. For at least the last 10yrs, that question has been repeatedly asked - and answered - over on the GlockTalk forums. Just FYI ... :cool:
 
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