long loaded 40sw ammo/10mm barrel?

[Steve RA]

I only did it once - at a match - where the RO handed me a round after a stage was finished and said it was the one that came out of my gun. I did not examine it closely and used it for my "Barney" round on the next stage. Luckily, the first target was at about 3 yds and the .40 bullet hit the target, although it keyholed. I saw the hole and fired again and kept on trucking. The RO on that stage gave me the case and asked if I was trying to save money by using a .40 once in awhile. No harm, no foul but the case ahead of the thick area at the base opened up to .45 size and split down the side.

I agree that if it slipped off the extractor and got ahead of another round it could cause real trouble, but, even if you had one loaded real hot, if it goes bang I really doubt if any appreciable pressure is developed with a .40 projectile in a .45 barrel.

[jmbaccolyte]

Yes, without a bullet that fits the bore the pressure will release pretty easily, but a maximum load in .40 is still 35,000 psi.

I agree that an obstruction in the bore, like a .40 round getting past the extractor into the .45 barrel and then someone firing a .45 round down the barrel would be worse and a more solidly plugged bore would be disasterous.

Edited September 11, 2013 by jmbaccolyte

[Duke Nukem]

You should call bullshit on yourself.

http://www.thegunzone.com/10v40.html

It will work for a couple shots but the extractor should blow off.

I'm going to call bullshit here; do you have first hand experience with this phenomenon? The case in definitely not driven forward when fired.

I do have experience shooting 40 in a 10 with no adverse effects on function or accuracy. I haven't fired tens of thousands of rounds this way, but I have talked to shooters on this forum who have shot that many rounds of 9x19 in a 9x21 barrel with no problems.

That being said, the real risk is that the rim slides in front of the extractor and your stage is over.

[Shadyscott999]

You should call bullshit on yourself.

http://www.thegunzone.com/10v40.html

It will work for a couple shots but the extractor should blow off.

I'm going to call bullshit here; do you have first hand experience with this phenomenon? The case in definitely not driven forward when fired.

I do have experience shooting 40 in a 10 with no adverse effects on function or accuracy. I haven't fired tens of thousands of rounds this way, but I have talked to shooters on this forum who have shot that many rounds of 9x19 in a 9x21 barrel with no problems.

That being said, the real risk is that the rim slides in front of the extractor and your stage is over.

Not really a necessary response. You posed BS and got called on it. Now you appear to be doubling down on your mistake/ignorance.

Edited August 20, 2014 by Shadyscott999

[kneelingatlas]

You should call bullshit on yourself.

Duke, I don't think there's any reason to get your hackles up, I think we're both interested in the same thing: some real data. When you said the extractor would blow off in a few shots I asked if you had any real experience with such an occurance and you were silent. I do have some limited experience shooting .40 out of my 10mm without any issues, but I have read that article, and had an experience with .380 in a 9mm which at least gives me pause:

I've also shot a few rounds of 40 in my 10mm. Apparently it can cause problems though:

http://www.thegunzone.com/10v40.html

I send my slide off for milling work, so I've haven't fired any more .40 through it, but I did do an interesting experiment with a .380 case which made it's way into my 9mm loads: it was a light steel load (3.15gr Clays under a 115) so I figured I'd shoot it and see what happens

It chambered fine and I could see the rim was securely behind the extractor so I shot it; it sounded funny as the brass fire formed to the chamber, but when I extracted it I could see what this article warned of: there was a scratch in the rim where it pulled past the extractor with the primer ignition then it was slammed back into the breech face, flattening the primer against the head stamp.

Granted, this is obviously less likely to happen with 40/10 because the rim is exactly the same, but I can now see how it could happen.

I'm not as interested in silly internet squabbles as I am in sharing real data and making informed choices, do you have any data to share?

[snertley]

I shoot .40 S&W out my 10mm ALL THE TIME. But it is a S&W610 revolver.