The 9mm case is slightly larger diameter than the .380. I would predict that your .380 reloads would not chamber properly, although it's possible there could be enough slop in your chamber to allow it.

Another issue is that the 9mm case is tapered, while the .380 is not, so even if it works, you'll probably wear out the cases after a few reloads due to the flexing of the brass. Might be extraction issues too, with the tapered case being wedged into the straight-walled .380 chamber.

Be careful!

 

Ah, maybe this is why you can't.

 

I've heard guys using a spacer washer to make a 44 magnum die good to reload 44 special... or is it the other way around? And same thing for 357 and 38 special.
Anyway, I don't see why 9mm dies couldn't be used to reload 9mm short.

 

You're asking for a lot of trouble to save a few bucks on the proper dies. Do it right and be safe, a kaboom will make the price of the dies seem really, really cheap.

 

Agree on the .380 dies vs 9mm. However, you can reload .357 mag with .38 special dies, and .44 magnum with .44special dies, you just have to place the bullet seater/crimp die a little higher.

 

You can do it. Not MY first choice.
The steps most likely to cause problems are flaring and crimping.
You can probably get the flaring tool adjusted low enough.
But crimping (removing the flare) needs to be done in die short enough to do it right.

You could use those dies "in a pinch", but I recommend spending the few dollars and buy dies for the specific case.
They will be better for it. And you eliminate the risk of leaving set " wrong" for the 9mm.

 

Ya know, there's certain places where it just doesn't pay to be cheap - having small, near explosions going off in your hand is one of them.

 

9mm dies are tapered. 380 cases are straight walled.

 

Argh. Well, I exclusively use lyman dies, I've had the best luck with them. But theirs is $50. I've tried the lee value sets, hated them, got stuck all the time regardless of proper lube, and the adjustments sucked on them. Other choice may be Hornady. Are they similar to Lyman?

 

If you get carbide dies, you won't need lube.

I like Hornady and RCBS the best. Dillon's dies have some good features, but their seating die has a rather coarse adjustment. If you'll only load the same type bullet to the same OAL, then you can take the extra time to adjust it then lock it down. You can take it apart for cleaning without losing the adjustment, too.

 

The reason you can get away with loading 380 on 9mm dies is that the short case does not go in far enough to get tapered. and that taper does the job of crimping [ sort of ]. Its a tricky adjustment! DR

 

The 380 case head diameter is .374 and the 9mm head diameter is .391. I have never tried it myself, but I don't see how the change head diameters. Maybe someone can explain.

 

Just because it CAN be done doesn't mean it SHOULD be done ! You are asking for problems that you don't want. .44mag/.44 special dies are straight wall , as are .357mag and .38 special. 9mm and.380 are totally different animals.

 

I think everyone here has touched on the need for proper tools. Get some carbide dies for .380.

The .380 is a low pressure round. Not likely to expand the body of the case. You obviously can get the bullet started. So whether your actually expanding the case or NOT resizing the mouth, the bullet fits.

 

Back in 93 and 94 I reloaded .380 for my wife's Bersa and yes I used my 9mm dies and 90gr bullets and there was never a problem and I used a Dillon Square D press but that was a long time ago so as they say things change, you might want to check with a smith of some years and get his input rather then listen to what you hear from some one without the qualifications and full reference.