Shooting 40s&w in a 10mm chamber

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Stats Shooter

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I have read a couple articles about doing this (Shooting 40s&w in a 10mm). The logic seems sound: basically the extractor of a G20 or 1911 holds the case tightly such that even though it headspaces off the mouth, it will work just fine.

And it shouldn't hurt anything.....similar to the jump of a revolver cylinder shooting 38sp or 44sp in a 357/44 mag.

I'm just winding if anyone has tried it and if so in what Gun?

Doing it would be an alternative to shooting plinking 10mm loads when practicing.
 
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I have heard it can be done. I would not do it absent an emergency.

I can't find any manufacturer who endorses doing it.

Edit: the risk of putting that much pressure next to my head in something that will "probably be fine" is not worth the minimal cost savings.
 
I've shot .40 in 10mm Glocks many times. Both the 20 and the 29. Works fine. They say it's hard on the extractor, but I never had any trouble.
I eventually bought KKM conversion barrels to do it right.
The only issue I ever had was with light .40 loads not locking the slide back, but factory power ammo always worked 100%.
 
Stats Shooter said:
The logic seems sound: basically the extractor of a G20 or 1911 holds the case tightly such that even though it headspaces off the mouth, it will work just fine.
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Until you consider that you're putting extra stress on the extractor, and that a dirty or worn extractor could cause intermittent failures to fire.

Additionally, it will create a crud ring in front of the case mouth, similar to what happens when you shoot .38Spl in a .357Mag revolver or .44Spl in a .44Mag revolver. This may result in failures to feed and/or failures to eject if you try to use 10mm without scrubbing the chambers with a wire brush first.

I put this idea in the same category as shooting .32 ACP in a .32 S&W Long revolver or .22LR in a .22Mag revolver: it'll work in a pinch, but there's a risk of mechanical damage or serious malfunctions, so I wouldn't recommend making a habit out of it. Buy a conversion barrel.
 
Unless the apocalypse makes ammo selection dire, I wouldn't consider shooting a gun with a cartridge other than the one for which it's chambered.

When I want plinking loads for my 10mm, I assemble plinking loads in 10mm brass.
 
I shot a couple hundred 40 S&W rounds through a 1006 I had. Never a problem, shot them like it was made for them.
 
Unless the apocalypse makes ammo selection dire, I wouldn't consider shooting a gun with a cartridge other than the one for which it's chambered. When I want plinking loads for my 10mm, I assemble plinking loads in 10mm brass.
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Agree, ... but even then I don't waste my limited time at the reloading bench doing that. My time there is spent cranking-out full-throttle 10mm handloads.

If I want to shoot "light-n-fluffy," I just swap-in an aftermarket .40 tube in my G20 or G29 and shoot real "FBI-Lite 10mm" loads, ... a/k/a the .40 S&W. These days, at least, factory .40 ammo is pretty cheap.
 
Agree, ... but even then I don't waste my limited time at the reloading bench doing that. My time there is spent cranking-out full-throttle 10mm handloads.

If I want to shoot "light-n-fluffy," I just swap-in an aftermarket .40 tube in my G20 or G29 and shoot real "FBI-Lite 10mm" loads, ... a/k/a the .40 S&W. These days, at least, factory .40 ammo is pretty cheap.
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I have 2 different 40 S&W pistols and a couple 5 gallon buckets of ammo I have made for them, so when I want to shoot .40, I will shoot 40. I was just wondering if folks have done it and if it works and if I didn't have any 10mm loaded up, if I could squeeze off a few 40's in my 10.

My 10mm loads run hot, 1250 fps for a 200 gr bullet in a 5" barrel. Really im just kind of curious about this, not planning to do it regularly.
 
I have yet to see or hear of a 10mm pistol blow up or injure the shooter or others nearby when shooting .40 S&W in it.

I have yet to see or hear of a .22 LR in a .22 Magnum do that, .380 in a 9mm do that, 9mm in a .40 do that (not advocating any of this btw), etc.

I would not be afraid to fire .40 in a 10mm to see which factory ammo or reloads work best, but I wouldn't do it regularly simply because it's not necessary. When it becomes necessary, then do it regularly.
 
Yes, but when I say experiment, I mean a magazine at a time with a few of the most popular brands of .40 ammo, both FMJ and JHP.

If after a hundred or so rounds fired there's no malfunctions, stop and do it sparingly thereafter until it's necessary to do it in some unfortunate event.
 
If you've read articles on the subject I'm not sure why you'd ask if it will work...

The better question is if it's a good idea and you have to decide that for yourself.

It'll work, but if done too much a crud ring will build up eventually and this will either prevent 10mm ammo from going all the way into the chamber or cause the fired brass to get stuck on the crud ring upon firing. The extractor will experience extra wear. How much? I've never heard of one breaking due to this but surely it is pushing the design of the extractor to the limit with each firing. Of course a new extra costs about as an box of ammo so in theory that's not a big deal if you catch it at an appropriate time.
 
If you've read articles on the subject I'm not sure why you'd ask if it will work...
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Reading an article and having a discussion with folks who might have done it before, or discussing the merits of it from more than one author's point of view is valuable imo.
 
I've done it (at least with Glocks) just to satisfy myself it will work if necessary. Accuracy and point of impact are exactly the same. Not something I plan to do on a regular basis, but I'm confident it'll work at least in my guns if I had to.

I can get 10mm ammo cheaper than 45 and it's not much more expensive than 40 S&W. I'd have to shoot nearly 8,000 rounds of 40 instead of 10mm just to break even on buying another barrel. I just shoot 10mm in the 10mm and use the 9mm Glock if I want to save money.
 
I've done it, works fine...

Clean the chamber good before after each use and it'll be fine.

Every Glock out there headspaces on the extractor anyway, at least the ones with factory barrels.
 
There are drawbacks, but in general shooting a short round (e.g., .40 S&W) in a 10 mm chamber will present no problems. In the cartridges mentioned, the pressures are close to the same (37.5k for the 10mm, vs 35 k for the .40 S&W) and the case dimensions are the same except for length. The major concern would be case support. In this case, as in others, the case is supported against the firing pin blow by the extractor. That is not going to harm a good extractor (which takes more stress in normal operation) but it can result in erratic primer functioning and inaccuracy. Plus, of course, the use of any shorter or less powerful round in a gun designed for something else increases the chances of mis-fires or mis-feeds, which is why the practice is generally not recommended except in an emergency.

Jim
 
I bought my 1006 when the 40 had been released and the 10’s were being surplused. At first, 10mm ammo wasn’t hard to find, mainly Silvertip.
But within a year, it became very hard to find, and at that time, ordering ammo wasn’t as common as now. Doubletap 10mm was pretty new.
About that time, I read an old magazine review of the 1006 by Ed Sanow, which seemed to endorse the use of 40S&W in the big pistol.
My LGS had Federal HiShok 155gn JHP cheap in 50rd boxes, so I bought some. The 1006 didn’t seem to care, accuracy was great, and it never jammed.
I don’t own a 10mm today, but if I did, it would be a G20, and I would stock up on 40 ammo when I found it cheap, for emergencies.
I probably would buy a 40 barrel...when I owned the 1006, the only aftermarket 40 barrel was by Barsto, which cost about the same as I paid for my pistol, and close to the cost of a new 40 pistol.
 
Stats Shooter said:
So, in summary:

Yes you can safely shoot 40 s&w in 10mm

It might gum up the chamber a bit

Most folks only do it in a pinch
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Yep, just clean it before using 10mm again.

Shouldn't ever be an issue to find .40S&W again, as many LEO agencies are dropping it
to follow the FBI's Dogma...of course, given how exceptionally dumb the FBI has been of late,
should anyone really be following them for ANYTHING?
 
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