Why does .380 not fire in 9mm guns?

[Sturmpanzer]

Might be a dumb question, but Ive heard the .380 called a 9mm Short, so why will it not fire in a 9mm pistol?... My guess is that it wont cyle the slide properly.....but, then again, a 9mm wont even fire a .380 if its locked in the chamber... Just wondering as I mixed up some rounds at the range from my big bag of loose ammo...

[PushPuller]

Just wondering as I mixed up some rounds at the range from my big bag of loose ammo...

Just reading this makes me sweat a little bit!

As far as I know it WILL fire just fine, but depending on the gun I think the biggest issue is cycling. Now go put a 9mm in a .380 and I doubt the results will be as minor.

[ammo.crafter]

Besides the obvious length difference between the two rounds, the shells do not have the same outside measurements.

See if you can tell which round has a straight wall and which has a slight inward slant.

[BillM]

Most straight (yes--I know 9mm is slightly tapered) pistol cases headspace
on the case mouth. The .380 is shorter than 9mm, so unless it gets grabbed by
extractor it will go too far into the chamber and the firing pin will not reach it.
If the extractor does grab it and hold it against the breechface--then it
will probably fire. 40 S&W in 10mm, 45 GAP in 45 ACP are more examples.

[mk70ss]

Quote:
Just wondering as I mixed up some rounds at the range from my big bag of loose ammo...

Just saying.....take 10 minutes and sort your ammo properly by caliber to avoid any accident. Not worth losing a eye, finger, etc over a few minutes of your time.

[tallball]

My FiL did it by mistake last year. The round fired. IIRC, the brass ended up getting stuck in the pistol. He put it back into his range bag and had to fiddle with it after he got home before he got the brass out. He still doesn't prefer to discuss it.

My own misadventure had a better outcome. It turns out that you just can't fit a 45acp round into a 40 caliber magazine, even if you're convinced in your own mind that it's the correct size.

[74A95]

It can fire in some pistols. There is a video somewhere on YouTube of this. Obviously, it's not recommended.

[JMag1]

Just don’t go there, and no, you aren’t the first over the years to ask such questions. Be safe.


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[T. O'Heir]

"...YouTube of this..." That doesn't make using the wrong ammo in any firearm a good idea. Youtube is not the place to learn anything. It's worse than Wikipedia.
The issue is headspace. .706" of excessive headspace. As mentioned, both cartridges headspace on the case mouth. Vs a .38 and .357 headspacing on the rim.
A 9mm won't fit in a .380. The .380 OAL is .984". The 9mm is 1.169".
You need to sort your big bag of loose ammo before you damage yourself.

[TXAZ]

Did someone want to apply for a Darwin Award?

There are actually quite a few cartridges that you can get to fit in almost-the-same-sized-chamber, sometimes they fire, sometimes they slide out the barrel, sometimes they go KA*******-BOOM.

Don't.

[Sturmpanzer]

Just thought it might be like a .38/.357.... So why do certain people call a .380 a 9mm Short...and yes,I will definitely sort my ammo better...

[mk70ss]

.38/.357 are not chambered by the use of the case mouth, they use the case rim to be properly chambered.

[Sturmpanzer]

AHHA!... Now I have "Knowledge".......like the old ESPN commercials... I knew it was something weird, and now I know... Thanks guys for the info...

[RJay]

I'm not saying to do it, It is not a good ideal . but 9X17 will chamber and fire in a 9X18 chamber, Did it by accident. . While back a friend loaded my magazine and handed it to me . I inserted it and fired away, didn't notice any difference in recoil and the shells didn't look bulged ( donated the empty's to to the range bucket ). The holes in the target were a large group for 20 feet which is what tipped me off. .after got home I wished I had kept them and measured them .

[Sturmpanzer]

I did the same thing..hence my question...will not be doing that again...the rounds are very similar and I just need to sort better... But why do people call it a 9mm Short....?? Thats misleading...

[Lexspeed]

Sturmpanzer, the Europeans called the 380acp the 9mm short. In Germany it was the 9mm Kurtz, the Italians called it the 9mm Corto, and Romanian's called it the 9mm Scurt. All meant the same 9×17 cartidge, which was 'shorter than the Luger 9mm×19mm.

[reddog81]

It's called 9mm short because that's it's nickname. It's a completely different round than 9x19 / 9mm Luger / 9mm parabellum.

Some 9x19 guns might shoot it but the slide won't cycle. It fires a 9mm bullet along with many other rounds.

[Sturmpanzer]

Gothca... Fantastic knowledge....never knew all that and it answered my question brilliantly... Thanks!..

[johnwilliamson062]

Most guns will fire and cycle it.
The round will be floating in the chamber as there is no rim to catch and the case mouth wont reach wither. At least not without leaving a gap at back.
The problem is the pressure. More that it could be just about anything than it necessarily is high. All sorts of weird pressure things could happen with case expanaion, not being firmly seated, etc.


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[hnusz]

My first and hopefully last ammo mix up was with my 45acp and my 10mm. Picked up a mag inserted it and racked the slide and a loaded round of 10mm slid out of the barrel of my 45. ������ Only one caliber of ammo on the table at a time.

[Aguila Blanca]

Originally Posted by Sturmpanzer

Might be a dumb question, but Ive heard the .380 called a 9mm Short, so why will it not fire in a 9mm pistol?... My guess is that it wont cyle the slide properly.....but, then again, a 9mm wont even fire a .380 if its locked in the chamber... Just wondering as I mixed up some rounds at the range from my big bag of loose ammo...

If the rounds headspace (locate themselves in the chamber) on the case rim, a .380 will be 2 mm deeper into the chamber and the firing pin won't touch it.

In 1911s, both the .380 ACP and the 9mm Luger are designed to headspace on the case mouth, but the extractor will hold a .380 cartridge in a 9mm gun, and it will fire. I have done it on an experimental basis. The result was a hole in the paper, but the gun didn't cycle.

In fact, the reason for my experiment was to see if I could find a recoil spring that would allow the gun to cycle on .380 ACP ammo. It didn't happen, and here's why. If you look up the respective cartridge dimensions, the .380 ACP is slightly smaller in diameter. They use the same bullets, but the brass case is smaller. When I fired .380 ACP in a 9mm barrel, the cases expanded visibly, beyond the point where I would feel comfortable resizing and reloading them. Yet, the cases were black with blow-by. They couldn't expand far enough to "obturate" -- they didn't seal the case to the chamber wall as the bullet left the case.

That meant I was losing a lot of energy. In fact, to test my theory and find a recoil spring that would work with a .380 cartridge, I ended up loading 9mm cases with 95-grain bullets intended for a .380, using a powder charge that generated .380-ish muzzle velocity. Firing those out of a 9mm barrel I was able to make the gun cycle, but the recoil spring was ridiculously light -- like 8 or 10 pounds, IIRC>

So you can fire .380 ACP outy of some 9mm pistols, but you won't be happy with the results.

Originally Posted by Sturmpanzer

So why do certain people call a .380 a 9mm Short...

Because that's what it's called in Europe: 9mm Kurz ("Kurz" is German for "Short"), or 9mm Corto ("Corto" is both Spanish and Italian for "Short"). .380 ACP is also called 9x17, and 9mm Luger is 9x19.

[1MoreFord]

Because it shouldn't???????

[Frank Ettin]

Originally Posted by Sturmpanzer

...I knew it was something weird,...

Nothing weird about it.

Cartridges intended to be fired in revolvers (or in single shot actions or multi-barrel break actions) tend to have a rim extending out beyond the diameter of the cartridge case. The rim will prevent the cartridge from entering too far into the chamber, and thus the cartridge headspaces on the rim.

Cartridges intended to be fired in semi-auto or automatic actions tend not to have a rim extending beyond the diameter of the cartridge case. They are designed in that way because rimmed cartridges tend to have more problems feeding from a box magazine (although they can feed okay from a tube magazine). Lacking a rim they headspace on the mouth or the cartridge case.

Therefore a revolver cylinder will accommodate and allow the firing of all rimmed cartridges which are dimensionally identical except for length. So, for example, a .454 Casul revolver will chamber and fire the .45 Colt and the .45 Schofield.

[Bill DeShivs]

a 1911 firing pin will extend quite a bit out of the breech face and fire a cartridge.
I have seen 9mm luger dropped into a Super .38 chamber fire in a 1911. Headspace was in tenths of an inch and case heads were flattened!

[jetinteriorguy]

It’s refered to the 9MM short because the bullet caliber is still 9MM but the case is shorter than a 9x19/9MM Parabellum.