Shooting .40 S&W

[kenzo]

I know this has probably been asked before, but in order to shoot .40 S&W ammo from a G20, do you need an aftermarket barrel, extractor, etc? If so, is the gun reliable when shooting the .40 S&W ammo?

I looking to buy a G20 and have plenty of .40 ammo I'd like to shoot.

regards

[klmmicro]

I have shot .40 SW from my G20 with no mods just to see how it would work. In 200 rounds there were zero misfeeds or problems. In a pinch it will work.

I do have a .40 SW conversion barrel for mine now and it shoots perfect. I did not want to shoot any more then the 250 test rounds with the rounds spacing only on the extractor. With the new barrel that cost about $75, it headspaces on the rim and I have the added advantage of standard rifling for lead loads.

[kenzo]

klmmirco thanks for the reply.

What conversion barrel are you using? With the cost of 10mm ammo, I think I'd rather practice with the .40 and use the 10mm once in a while. In other words, I'd like to use the G20 as a .40 pistol for plinking, range, etc. with the advantage of using full power 10mm for wilderness hikes / self defense.

regards

[Shotgunner]

I have shot my G20 w/ low recoil .40 rounds. Worked flawlessly. Buy a box of .40 and try it out. Accuracy and reliability are +++.

-Shotgunner.

[snewbie]

This is the first I have heard of being able to shoot 40 s&w out of a 10mm without a conversion barrel. The idea makes me nervous to say the least.

[RyDC]

Not that I'm advocating it, but:
While I was shooting both a Model 27 and a Model 20, I decided to experiment by shooting a few .40's through the stock 10mm Model 20 barrel. I had zero malfunctions, and the .40s grouped fairly well. I've had exactly one malfunction in this Glock, and that was with 10mm CCI Blazer Aluminum. The WWB .40 ran flawlessly. I examined each casing after it was fired, and was pleasantly surprised to see that it was not bulged or deformed. Several manufacturers make (typically 1911-based pistols) pistols that will shoot both out of the stock barrel, but they typically have dual extractors, as the extractors provide the headspacing when shooting .40 out of a 10mm chamber.

The Glock has only a single extractor, but it is big enough that it provides enough purchase to hold the round.

In summary: it worked for me. It may not work for you.

[surfinusa]

I got a federal 40 S&W conversion barrel for my G20. It was cheap and works exactly how its suposed to. I won't shoot ammo out of guns that weren't designed for it.

There was a thread here a few months back where a guy shot 40 out of his G20 and every primer was pierced.

[Bravo-Four]

In no way would I consider myself an expert on GLOCK internals, but you would think that a .40sw round would sit backwards quite a bit in the chamber from where the 10mm normally rests. Meaning it would fire before the bullet is actually seated within the safety blanket of the rifling.

[Masque]

Aside from the fact that the round is headspacing on the extractor instead of on the end of the chamber, and that therefore this is a "bad idea" from a lot of perspectives, and that you're ... well, the point is, this is probably not a good plan.

IF you do it anyway, do consider that you may develop fouling on the inside of the chamber, and that sufficient fouling/buildup could result in a situation where a 10mm cartridge wouldn't seat fully, due to the buildup around where the case SHOULD be headspacing, and thus could - hypothetically - lead to firing slightly out of battery.

For those of you who don't tune in regularly, that's a very bad thing. So do make sure you scrub up afterward, yeah? We like our GLOCKs in one piece. :) (Okay, 37-39 pieces, but all in the correct shape and proportion.)

[snewbie]

Originally posted by surfinusa
I got a federal 40 S&W conversion barrel for my G20. It was cheap and works exactly how its suposed to. I won't shoot ammo out of guns that weren't designed for it.

There was a thread here a few months back where a guy shot 40 out of his G20 and every primer was pierced.

Ive looked everywhere for one of those cheap conversion barrels, but to no avail.

[RyDC]

Originally posted by Masque
Aside from the fact that the round is headspacing on the extractor instead of on the end of the chamber, and that therefore this is a "bad idea" from a lot of perspectives, and that you're ... well, the point is, this is probably not a good plan.

IF you do it anyway, do consider that you may develop fouling on the inside of the chamber, and that sufficient fouling/buildup could result in a situation where a 10mm cartridge wouldn't seat fully, due to the buildup around where the case SHOULD be headspacing, and thus could - hypothetically - lead to firing slightly out of battery.

For those of you who don't tune in regularly, that's a very bad thing. So do make sure you scrub up afterward, yeah? We like our GLOCKs in one piece. :) (Okay, 37-39 pieces, but all in the correct shape and proportion.)

Liked that last line there, masque. I try to avoid "uncommanded disassemblies" of my firearms (I've had a couple kabooms, one in a little Marlin .22 and one in an SKS), so I try to be extra careful now.

When I shot .40 through the 10, I would put one round in the magazine, fire it, exam the brass, and then put the brass on my shooting table. Then load two, then three... checking every piece to ensure the primers weren't flowing and the brass wasn't bulging, and that the extractor wasn't breaking the rim of the cartridge.

When I got done, I checked the chamber for fouling; there was no more present than I would have under normal 10mm shooting circumstances. I was using Winchester White Box; I've fired several brands of ammo that were terribly dirty in this pistol (HSM, if anyone else uses it, among others), and I imagine that those probably would have induced more fouling than the WWB. The chamber is where the highest temperatures are achieved, and thus the place least likely for significant fouling to occur.

But like you said, it's not a good plan. I tested just for the sheer sake of testing it; while I have yet to hear of anyone kabooming a 10mm Glock (kabooms in 10mm Glocks aren't that common anyway, as they are arguably the strongest built pistol Glock makes) using .40 ammo, the risks of something inadvertent happening outweigh the benefit.

[badkarmaiii]

I would like to see someone make a chamber insert ring like the inserts for rifles. For the 10mm/40 this would be just a ring that fills in the chamber allowing the 40 to headspace on the rim. Should be cheap, too.

-MIII

[klmmicro]

Originally posted by badkarmaiii
I would like to see someone make a chamber insert ring like the inserts for rifles. For the 10mm/40 this would be just a ring that fills in the chamber allowing the 40 to headspace on the rim. Should be cheap, too.

-MIII

While it might work, it is really easier to just get a "conversion" barrel. The difference between the 10mm and .40SW is pretty small. The ring would be so small and to bring up reliability issues. It could work its way loose and cause all manners of problem.

[Rusty Phillips]

confession

I have a G20 that has never seen a 10mm

by the way - a G21 will run on 45 gap too!

[Masque]

Originally posted by Rusty Phillips
confession

I have a G20 that has never seen a 10mm

by the way - a G21 will run on 45 gap too! Oh, you have to tempt me, don't you.

How's the accuracy? Good enough for practical competition?

[G29_10mm]

Tempt you?

Why spend the premium (~$50-80) on a G20 when you're not using it with the ammunition it's manufactured for. Just buy a damn G22.

[Masque]

Sometimes 10mm isn't available. Sometimes ranges require that you shoot only what you buy there, and when they're out of 10mm, having .40 as a backup option would be nice.

So if you feel like buying me an entirely separate weapon for those days, I'll consider shooting the G22. Until then, however, I'll stick with the G20 and G29 that I much, much, much prefer.