Resized 9mm with 357mag die.

[357mag357]

So I wasn't paying attention and resized some(300) 9mm with a 357mag die. Can I still use it or do I need to resize it with the 9mm die? I am really embarrassed to share this but it is what it is? Thanks for any information.

 

[AgPilot]

I’d poke some 45 bullets in em and go with it!!!
Just kidding. I am not sure and would love to hear what to do in this situation.
P.S. if that brass can’t be used I will share some with extra 9mm Ya if needed.
Robert

 

[Fine Figure of a Man]

Run it through your 9mm die.

 

[Walkalong]

Try one and see what your neck tension is, might be ok, if not.......

 

[FROGO207]

Agree with above. 9MM is .355 and 357 bullet is .357. Run them through the correct sizer and flare as usual.
I have put several safe practices in effect over the years like one propellant and one set of dies on the reloading table at a time. Also put a post-it on my powder measure with caliber, bullet weight, powder type, and weight. This helps if you leave things and come back so you can verify you are still doing things correctly.

 

[merlynski]

The .357 Mag case is a straight wall case of .379" diameter, the 9mm is a slightly tapered case, .380 at the mouth to .391 near the case web/head. The .357 Mag die may have already sized it smaller than nominal. Get out your calipers and measure them. The difference at the mouth is only 0.001, I would guess the neck tension would be OK after you run the 9mm expander die into it, and seat a bullet. The case web being undersized a bit may affect accuracy, but my thinking is it probably won't hurt anything, and will expand back to nominal after shooting them.

Data quoted from Lyman's 50th

 

[357mag357]

Thank you all for the information.