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Old April 2, 2014, 10:57 PM   #1
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Dumb question

Would it be possible to fire a 380 round in a 9mm pistol?
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Old April 2, 2014, 11:10 PM   #2
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Uhh, probably not. Here's how I understand it. . .

The problem is that the brass mouth is supposed to headspace up against the inside of the chamber - there's a ridge where the chamber ends and the barrel rifling begins. (I think there must be a better way to word that - sorry)

Anyway, the 380 brass is 2mm too short, so it will most likely fall inward too deep (by 2mm) and then the striker wouldn't be able to reach the primer. The ejector may be able to hold it in place, but I doubt it.

The experts who know more than me will probably chime in.

At any rate, it's not as simple as a 38 Special / 357 Magnum kinda thing, if that's what you're thinking.
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Old April 2, 2014, 11:45 PM   #3
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Why? I'm paying ~$0.30/round for 9mm, and ~$0.60/round when I can find .380.

Don't know the answer (suspect Nick is right - it might work, but not very well), but the economics make it moot.
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Old April 3, 2014, 12:52 AM   #4
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Yes it's possible if the ejector hooks the rim to prevent the round from settling too deep in the chamber. Definitely not recommended though- you might get a face full of hot gasses or a blown cartridge.
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Old April 3, 2014, 01:13 AM   #5
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I found out early on in my semi-auto experience that yes, a .380 (9mm Kurz-or 9mm Short) will in fact fire in a 9mm. At least it did in my Beretta 92FS. Somehow at the range one day I got a round of. 380 for my Browning BDA loaded into the 92 mag. I shot the mag with no problems until I got to the .380. It cycled into battery, then fired and hit the paper about where it should. Only problem was the slide didn't move back far enough to spit out the brass(if at all), so no BANG on the next one. When I racked the slide to see what was up, out popped the. 380 brass looking none the worse for wear. I've made sure that combo has never happened again.
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Old April 3, 2014, 08:51 AM   #6
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As has been mentioned, the extractor can keep a shorter case within reach of the firing pin.
While not recommended, 9mm rounds can work in .38 supers, too.
Could come in handy in an emergency, if suitable ammo is not available.

One day at the range, the fellow at the next bench was shooting nothing but 9mm out of a 1911 .38 super.
He said he had got into the habit when he couldn't get the proper ammo.
So, he just kept doing it and had been for years.
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Old April 4, 2014, 01:53 AM   #7
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I was sizing and cleaning some brass last night. After sizing them and cleaning them, lo and behold I found one 380 brass. I thought I'd fired all of these at some point but maybe not.
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Old April 4, 2014, 01:08 PM   #8
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I fired one accidentally in my SIG 228. Nothing bad happened. The different report and recoil caught my attention and I saw the ejected case hit the floor. The second I saw it I knew what had happened. I consider myself lucky. Not so much for what happened but for nothing bad happening from my carelessness. It was either me or my son that loaded that round into the magazine. I think it was probably me. I often load magazines without really watching what I am doing. Kind of on auto pilot often talking to my son. I now pay attention to what I am doing. I got off cheap for being so complacent. Complacency and firearms make bad company.
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Old April 4, 2014, 01:31 PM   #9
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It's not a dumb question.
It is a dumb idea.

You'll find some of these pieces on public ranges... it's more common to find the 9mm rounds shot from a .40cal and .40's shot from a .45. I would like to hope that it's usually done in ERROR and not on purpose. I think where it happens most often is when two shooters are sharing very similar guns and magazines get mixed or careless loading of the magazines happen, especially if the more novice of the shooters is handling the ammo at that time.

It's not a huge "safety" issue. When the round is smaller, and neither the cartridge case nor the bullet are RESTRICTED in any manner, pressure can only drop with the extra space.

In the case of .380 being discharged in a 9mm, the cartridge case is a wee-bit smaller, so it will fire-form to the chamber and the bullet, being the same diameter, will offer the "proper" level of resistance in the bore. What will most likely happen is that the .380 round will discharge almost exactly as it's designed, and send that bullet out at typical .380 speeds. The 9mm pistol may or may not cycle. The brass will be slightly blown out to the spec of the 9mm chamber. Remember that all .380 ammo built to proper spec runs at a much lower pressure than proper 9mm ammo does.

If you shoot a 9mm in a .40cal, you're running the SAME pressure ammo, but without the resistance of the bullet fitting in to the bore. A .356" 9mm slug will simply fall down a .40cal bore with zero resistance. So when you pull the trigger on that, you'll NEVER reach full pressure because the bullet has no genuine resistance.

.40cal discharge in a .45 pistol is a better example: Here you have ammo that is significantly higher in pressure than the pistol for which it happens to be in. Sounds like disaster... but it's not. The .401" bullet meets no resistance in the .452" bore, so the 35k PSI max never gets reached, or anywhere near, because there's no real resistance to max it happen.

It's like a firecracker. Rip one open and you find just a dusting of propellant. So little, it's almost unbelievable. But if you wad it up TIGHTLY in a tiny space with all that tight paper, it becomes a little pressure-bomb and it'll take your finger off if you let it.

Putting the wrong ammo in any firearm is almost always a genuinely BAD idea and could also lead to other related issues, but it's not always going to be a catastrophic event unless the math adds up. Try it with some bottle neck rifle rounds... where the shell fits but the bullet is LARGER than the bore and now you've got a potential DISASTER on your hands.
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Old April 4, 2014, 02:38 PM   #10
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Old April 4, 2014, 02:41 PM   #11
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I almost can't believe I fired this round because I would have loaded it using a Lee disk powder measure and I don't think it would have triggered the measure and belled the case enough to seat the bullet. If I did fire it, I saw no ill effects.
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Old April 4, 2014, 02:45 PM   #12
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Are you saying that you built a round of handloaded "9mm" but you constructed this in a .380 Auto cartridge case?

That would be -FAR- more dangerous simply because you are putting the components designed around the 9mm in to a smaller case with a smaller space for combustion. All else being equal, you RAISED pressures in this situation, if you actually succeeded in doing this.

How much? Couldn't tell you. Someone with the Quickload software could make a mathematical estimate.

Best way to find out if your tooling would have pulled off this reckless stunt is to attempt to repeat the construction of the round willfully.
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Old April 4, 2014, 03:39 PM   #13
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As stated you can but not a pleasant experience.
On several occasions at the range I have seen 380 ammo get into some ones 9mm and loaded and shot.
Face full of gas, burnt hands and damaged mag.
Not pretty.
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Old April 4, 2014, 11:32 PM   #14
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Would I do it deliberately, no.

However, accidentally I shot a 45 GASP, in my 45 ACP

You might as how and why and the answer is I had never heard of 45 GASP so when I saw 45 auto on a box I assumed ...... the road to hell being paved with those sorts of things (or sometimes just the hospital).

Fortunately, whatever the dynamics, while it fired, it did not eject, after the 2nd one it was something is wrong here....... while not swift, I have seen worse refusal to accept reality. On the other hand when shooting the first hick-up should be investigated thoroughly.

No damage done other than $25 or so wasted on GASP ammo.

Well, I curse gaston gasp to this day for his ego, but then I curse him for a lot of things.
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Old April 5, 2014, 02:13 AM   #15
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I've fired a 40 out of a 45 once
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