.380 in a 9mm revolver

[evan price]

Just a stupid question-

Another thread somebody asked about the (bad) idea of trying .380 auto in a .38 spl revolver. Obviously a bad idea.

But I had the thought- if you had one of those 9mm revolvers, why wouldn't .380 work in that? Both are .355 nominal, both have similar cases, only difference is 1mm less OAL which in a revolver shouldn't matter.

I don't own a 9mm revolver, just wondering.

 

[Jim Watson]

That is not the "only difference"

The .380 case is straight sided and thin walled which means it will bulge and maybe split in the tapered 9mm P chamber. Even the multi caliber Medusa did not work well with it in the only objective report I ever saw. The small rim was prone to slip by the trick extractor in the compromise chambers.

Oh, by the way, its TWO millimeters.

 

[Claude Clay]

actually it is 2 mm shorter.
no harm / no foul shooting it in a 9. just not good accuracy and will not cycle/feed reliably.

 

[The Lone Haranguer]

I don't have a 9mm revolver, but I do have some .380 and 9mm cartridges on hand and did a little measuring with a caliper. The .380 case is not just shorter (by .090"), it is also .015" smaller in diameter ( measured at the extractor groove). With no rim for headspacing, the .380 would drop so far into the charge hole that the primer could not be struck by the firing pin. It is unlikely that a 9mm moon clip would hold the cartridges for headspacing, either. Finally, even if you got it to fire, the case would likely severely swell and might even burst.

 

[Clipper]

Since .380 is way more expensive than 9mm, what would be the point?

 

[the naked prophet]

Since .380 is way more expensive than 9mm, what would be the point?

I would assume, if you were in a life-or-death situation and all out of 9mm, but found some .380 (but didn't find a gun to match). You could make do for a few shots until you could get to some correct ammo or another gun.

 

[mainmech48]

Since 2 mm is roughly equal to 0.08". I doubt that a .380 would even fire reliably in a 9mm revolver unless you could get it to stay put in a clip of some sort. Seems to me that it'd slide too far into the chamber for the FP to ignite the primer. I may be wrong, but I still don't think it's a premise that I'd be willing to test personally.

 

[ants]

OK, I just did it. One of my 380auto reloads, in a Beretta 92FS. It fired the cartridge, and the bullet when straight to the center of the target at 7 yards. It didn't have enough power to cycle the slide, so one would have to cycle manually each time.

The empty brass case was expanded slightly larger than usual. I put it in the 380auto die and resized it normally. If reloaded and shot more than twice, I'm sure the case would split sooner than shooting it in a true 380 chamber. Even in a 380 chamber they split after a few firings.

After shooting it, I found myself glad that I used an fmj bullet. A lead bullet would have shaved lead on the front edge of the 9mm chamber, which you know is machined to headspace the 9mm cartridge on the case mouth. Enough deposits and it won't chamber a 9mm cartridge any more.

There are more cons than pros, it would seem. I'm glad I tried it, but now it's a boring subject.

 

[rcmodel]

But the question was about a 9mm revolver.

The extractor in your auto pistol held the .380 back so the firing pin could hit it.

But a 9mm revolver has neither an extractor hook, or a long enough firing pin for reliable ignition.

If you pointed a revolver straight up, the .380 would fall back against the recoil shield and probably fire.

If you pointed it down, it probably wouldn't.

rcmodel

 

[Jim Watson]

As rc said, the original quesion was about a 9mm revolver.

There was one government agency that trained in malfunction clearance by including the occasional .380 in 9mm Beretta magazines. As ants found, the gun will feed and fire, but not function. That would leave the trainee with a hangup to clear.

 

[evan price]

What I was getting at, having never owned or shot a 9mm revolver, was the fact that the moon clips would hold the case in the proper position to be struck by the firing pin.

Or do 9mm revolvers not use moon clips?

Oh, and Jim, yes, I brain-farted: It's 9x19 vs 9x17, for some reason Makarov (9x18) stuck in my head.

 

[Shade00]

I actually thought about this exact same question no less than 2 hours ago. Glad I didn't post a new thread. 9mm revolvers definitely use moon clips - and I am certainly interested to hear whether a 9mm Parabellum revolver would fire 9x18 or 9x17 reliably. It certainly has no practical application since 9mm Parabellum is cheaper than 9x17 and usually a few pennies cheaper than 9x18, but would still be interesting to hear (let's say I bought all of the 9x19 Monarch boxes at Academy and wanted to use the 9x18 Monarch ).

 

[Jim Watson]

Not all 9mm revolvers use moon clips. The Ruger Speed Six and SP 101 do, along with the S&W 940 and the occasional Astra. But the S&W 547, Phillips & Rogers conversion and Medusa revolver; and I think the Manhurin 73 use trick extractors to get along without clips.

You might could hang a .380 on a clip and get it to fire, but as I said they did not work well in the Medusa.

Oh, by the way, Shade, don't put a so-called 9x18 Makarov in ANY 9mm P gun.

 

[Packman]

The Ruger Blackhawk (I think) comes in a convertible .357/9mm model. No clips, I think it just uses headspacing. Single action though, maybe that changes things. I don't know enough about the gun.

Oh, by the way, Shade, don't put a so-called 9x18 Makarov in ANY 9mm P gun.

Why, what happens?

 

[mainmech48]

Same result, or lack of one, would happen in the Ruger SA. The chamber dimensions remain essentially the same regardless of action type or brand.

Assuming (and I don't think it's likely) that you could get a 9x18 Makarov round far enough into a 9x19 Parabellum chamber for the action to close into full in-battery position and fire, none of the most likely results would be very pleasant for you or the gun.

As mentioned, the 9x19 case is tapered and the nominal bullet diameter is 0.356". The 9x18 Mak's case is straight-walled and the nominal bullet diameter is 0.364". In the above situation the resulting pressure spike would be very considerable indeed and, quite possibly, catastrophic to the point of 'spontaneous disassembly'.

 

[TehK1w1]

+1 on not trying it with the Makarov. It probably would not chamber anyway due to the larger diameter and straight-walled case. I do know that a 9mm Parabellum round will chamber in a 9mm Makarov. (again, bad idea, probably an even worse idea actually)

 

[Brian Williams]

It is chambered for 9mm, shoot 9mm in it.
Dumb idea to shoot any gun with ammo not designed for that chamber.

Do Not Be Stupid.


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