Shooting .40 in a 10mm (That's not a Glock)

[TruthTellers]

It's been pretty well established that .40 S&W can be shot without issue in 10mm Glocks without any modifications, but I'd like to know has anyone ever tried shooing .40 in unmodified 10mm's that aren't a Glock? Did it work or did it cause issues?

[Aguila Blanca]

.40 S&W can be fired in 1911s chambered in 10mm, but to do so means that the case is headspacing on the extractor rather than on the case mouth. Accuracy may suffer, and if it's done frequently it may result in extractor failure.

[BJung]

My youngest brother shoots .40 S&W through his Glock, loves it, and has been doing it for years.

[TruthTellers]

Originally Posted by burbank_jung

My youngest brother shoots .40 S&W through his Glock, loves it, and has been doing it for years.

Did you miss the part where I said "I'd like to know has anyone ever tried shooing .40 in unmodified 10mm's that aren't a Glock?"

[stephen426]

Interesting... The 10mm will cycle with the .40 S&W reliably? I would figure weaker spring would be required/

[TruthTellers]

Originally Posted by stephen426

Interesting... The 10mm will cycle with the .40 S&W reliably? I would figure weaker spring would be required/

There's a decent amount of 10mm ammo out there that is not much more powerful than .40, so I'm thinking that the companies than make a 10mm gun ensure that it can run these low end, lower recoiling loads reliably, so a .40 with its shorter case shouldn't be a problem and as the gun gets shot over its lifetime, the recoil springs lose some power.

[jmr40]

Interesting... The 10mm will cycle with the .40 S&W reliably? I would figure weaker spring would be required/

I know your looking for non-Glock data, but my reply is to this question. At least on my Glock the much heavier slide on the 10mm is part of the equation. Glock designed their G20 around the 10mm cartridge then modified it to work with 45 ACP.

Everyone else took existing 45's and modified them to work with 10mm. I don't know if they make the slides any heavier on other 10mm pistols or not. I don't see how a 1911 slide could be much, if any heavier in 10mm than 45. I'm guessing that a different recoil spring may be required for reliable functioning on some non-Glocks shooting 40 S&W. But that is just a guess.

But both my G20 and G29 function reliably, and accurately with no POI change with everything from light 40 S&W loads up to the hottest Buffalo Bore and Double Tap loads.

[Dan-O]

Done it in an unmodified 1006

[Forte S+W]

I've seen a lot of folks on the Smith & Wesson Forums saying that the 10mm 3rd Gen pistols like the 1006 and 1076 can shoot .40 S&W without issue.

Based on what I've heard, I would surmise that practically any 10mm pistol can safely fire .40 S&W because literally every 10mm pistol I've heard of will headspace .40 S&W on the extractor and provide adequate case support to prevent blowouts.

That being said, a lot of commercially available, factory loaded 10mm ammo are the old FBI Loads, which are literally just .40 S&W in a longer case, with any minor difference in performance printed on the box being a result of the use of a longer test barrel. (Seems like most 10mm ammo is chronographed from a 5" test barrel while .40 S&W is more often chronographed from a 4" test barrel.) Furthermore, I've seen a humiliating amount of folks who like to brag about the incredible power of their 10mm handcannon on forums, then post pics of their firearm amidst boxes of 10mm FBI spec ammo, evidently completely unaware that their mighty 10mm is being fed ammo no more powerful than .40 S&W, so there's a possibility that a lot of the folks who are shooting .40 S&W out of their 10mm pistol are using pistols which have already been setup to function with FBI spec 10mm loads, hence why they function perfectly with .40 S&W.

Personally, I would like to hear from some folks who shoot full power 10mm loads and have tried .40 S&W out of the same pistol, as I wonder how well .40 S&W would function in a 10mm pistol with the proper recoil springs installed to handle full power 10mm Auto.

[disseminator]

I can speak to the recoil spring question: I have a 40 conversion barrel for my glock 20 and it works 100% with the stock spring. I've even run it through defensive pistol classes in that configuration. It's a really sweet 40 and very reliable too.

[corneileous]

Originally Posted by TruthTellers

There's a decent amount of 10mm ammo out there that is not much more powerful than .40, so I'm thinking that the companies than make a 10mm gun ensure that it can run these low end, lower recoiling loads reliably, so a .40 with its shorter case shouldn't be a problem and as the gun gets shot over its lifetime, the recoil springs lose some power.

See, it’s because of that... is why I’m so selective on what 10mm ammo gets bought for and shot from my Sig P220 Elite; it may not be an issue but I bought a 10mm for the sheer power that a 10mm is known for. I didn’t buy one to essentially shoot basically a 40 S&W in a longer case, I want full
10mm loads.


Sent from my iPhone using Tapatalk

[TruthTellers]

Originally Posted by corneileous

See, it’s because of that... is why I’m so selective on what 10mm ammo gets bought for and shot from my Sig P220 Elite; it may not be an issue but I bought a 10mm for the sheer power that a 10mm is known for. I didn’t buy one to essentially shoot basically a 40 S&W in a longer case, I want full
10mm loads.


Sent from my iPhone using Tapatalk

I've no argument against that, it's one reason why I'm planning to reload the 10mm so I can get that extra power and not be forced to pay big money for that ammo from Underwood or Doubletap, but I also like the ability of the 10mm to go down to .40 power levels.

10mm really seems to be the most versatile semi auto pistol caliber.

[the duck of death]

"QUOTE"
I didn’t buy one to essentially shoot basically a 40 S&W in a longer case, I want full
10mm loads.

If you handload try this--load 40 long IE the same length as a 10mm load. I've done this in a G29 w/14.5#9/180 coated. Best to use 180gr and heavier so there is enough bullet length to seat.

That folks, is a hot "10mm" equivalent load.

[Dan-O]

The .40 case is structurally stronger than the 10mm case as well.

[the duck of death]

If the structure of the 10mm case is exceeded--your in more trouble than worrying about case strength.

[Dan-O]

I stand corrected. The 10mm case is rated at about 2000 psi more than the .40.

I thought since it had a small primer pocket it’d be higher.

[Hammerhead]

I have a book on the 1911 that shows two blown 40 cases fired from a 10mm 1911.
The case gets ahead of the extractor, and the long firing pin on a 1911 is able to reach it.
Unlike a Glock with very limited firing pin protrusion.

I shot hundreds of 40 ammo in my stock Glock 20 and also with a 20 pound recoil spring on a steel rod. Never a problem.

Then I bought a KKM 40 conversion barrel and shot thousands more 40 cases.
I liked the conversion. At the time .40 brass was everywhere and small primer were easier to find than large, so it was a handloaders dream gun.
Very accurate and soft shooting as a 40. Very reliable too.

[amd6547]

I had a 1006 for a while...at that time, 10mm ammo got hard to find. I had heard about shooting .40 in the 1006 in an article by Ed Sanow in a magazine.
My 1006 shot it like it was made for it, no problems at all.

[TruthTellers]

Seems like other than the 1911 that .40 can be shot in a 10mm without issue.

That's cool to hear and the reason I asked is I decided it was time to get a 10mm after thinking about whether a .45 Super or .460 Rowland would be better, but the more I thought about it, the more I came to conclude that 10mm is all the power I need and want in a semi auto pistol and in the future it's more likely that 10mm brass is going to be more common to find at the range than .45 Super or .460 Rowland will be.

I mean, when companies like CCI, Fiocchi, Magtech, and PPU are making cheap ammo for 10mm, people are gonna buy it vs .45 Super ammo that costs over $1 a round.

The ability of 10mm's to also shoot .40 gives it the same advantage that the .45 Supers also have in shooting .45 ACP.

I think I made the right decision buying a 10mm.

[Bozz10mm]

I've got a Non Glock 10mm (S&W 1006) but I've never tried shooting .40 cal in it. If fact I don't even have any 40 cal. If it's cheaper than 10mm, I might give it a try some time.

[Big Shrek]

Works for EAA Tanfoglio Witness 10mm also.
You can shoot ,40 short & wimpy all you want.

[FotoTomas]

A Glock 29 is now on my wish list as a versatile ammo hog. My Glock 22 has a .22 kit, 9mm and .357 sig conversion barrels to go along with its .40 caliber. I want to do the same to a 10mm now.

[GarrettJ]

Originally Posted by Hammerhead

I have a book on the 1911 that shows two blown 40 cases fired from a 10mm 1911.
The case gets ahead of the extractor, and the long firing pin on a 1911 is able to reach it.

That didn’t sound quite right. So I had to go check for myself.

Using a Colt Delta Elite, I see the firing pin could indeed contact the primer of a .40 that was out in front of the extractor and seated at the end of the chamber. However, being seated more deeply in the chamber, the case would be fully supported at the moment of firing. Much more so than any 10mm or .40 that was chambered with the case head up against the breech face. This is actually an example of a fully supported case. See below.



For comparison, here is what a 10mm looks like when chambered correctly. Notice the unsupported area in front of the extractor groove. This is normal.



Now what would happen if one fired the deep-seated .40, without the mass of the slide directly behind it, the case would be shoved backward, snapping the rim past the extractor until it comes in contact with the slide, and then continue cycling as normal. So true, the case would begin to move out of the chamber while the pressure was higher, but it would still be stopped at the point where the recoil cycle usually starts, and with the same amount of uspported case at this point.

I suspect the instance you read about was caused by a gun with an excessive unsupported area of the chamber. I understand 10mm brass is thicker in this area, and so the issue never manifested. When a thinner .40 case was fired in this particular chamber (with the rim either in front of or behind the extractor), the case was insufficient for the excessive chamber and it failed.

It’s a thought, anyway.

FWIW, I’ve fired a couple hundred .40s through a Colt 1911 without issue, and through a couple of Glock 10mms as well. The only “issue” I have noted was that having the case head not pressed firmly against the breech face allows for excessive primer flow. Reading the primer gives the impression of a massively overpressure cartridge. However, it is just from having insufficient support for the primer.

Having said all of that, I have guns chambered in both calibers, so I can shoot the “correct” cartridge in each gun. But should I find myself with only a 10mm and no ammo was available, I would not be uncomfortable substituting .40 for use.

[Hammerhead]

I suspect the instance you read about was caused by a gun with an excessive unsupported area of the chamber. I understand 10mm brass is thicker in this area, and so the issue never manifested. When a thinner .40 case was fired in this particular chamber (with the rim either in front of or behind the extractor), the case was insufficient for the excessive chamber and it failed.

That's your assumption, not mine.
I'm just passing along a warning from a reputable source, not internet speculation.

[Jim Watson]

In the Golden Age of surplus guns, there were a lot of Spanish 9mm Largo pistols sold surplus. The story was that in particular, the Astra 400 was an "any 9mm" gun capable of being shot with 9mm P as well as its intended 9x23 Largo/Bergman Bayard round.

And it was, usually. The 9x19 would "headspace" on the extractor or on the case/chamber taper and all was well. But if a 9x19 got ahead of the extractor and the long protrusion firing pin set it off, it did not just push back "snapping under the extractor." Maj. Geo. C. Nonte was a big gunzine contributor at the time and he showed pictures of blown primers where the case expanded enough to hold in position forward with no head support.

So I think you are taking a bit of a chance shooting .40s in a 10mm DE even though you can get away with it in a Glock or other gun with limited firing pin protrusion.