gonna sound stupid but, oval case mouths

[oley55]

More and more of my 38/357 cases are developing an oval case mouth. Once they have taken an oval set, resizing does not fully remove it. Rather it takes a gentle squish with some pliers. A bit of a pain when reloading cast bullets.

These are all many times loaded brass. Could this be an indication of over worked brass or is something else going on.

fyi, all are sized in a 30 year old carbide CH die.

[shootbrownelk]

Finish the job with the pliers and squish those cases, toss them in your junk brass container. They did their job.

[mehavey]

I admit to being confused by a revolver cylinder producing "an oval case mouth"
after firing. Can you post a pic or two?

(I'm particularly fascinated as to how the case expander/flare die wouldn't cure
any such anomaly no matter what.)

[reddog81]

I've seen oblong 45 ACP cases that were dented upon extraction from an old military 1911. I can't even begin to fathom what would cause and oval case mouth on a 38 special. What kind of gun are you shooting them in? When does the oval develop?

[Nitescout]

the only time I have seen oval case mouths on .38 or 357 mag is when someone walks on them...The expander ball in your sizer die will iron out the oval shape back to round...If that doesn`t work, well...I don`t know???

[oley55]

they go oval on me after having been resized. I generally deprime, pin tumble, size and then store until ready to load for whatever (levergun and revolvers). that's when I find the oval cases.

I had previously found this from a bunch of old mil crimp 38spl I had been sitting on for twenty years and chalked that up to 300 cases settling down on themselves for years. Now I am finding recently processed 357 mag cases in the same condition. Not all just some. both Federal and Rem.

[oley55]

The expander ball in your sizer die will iron out the oval shape back to round...If that doesn`t work, well...I don`t know???

expander ball for straight walled cases? mine doesn't have one.

[mehavey]

Are you saying the CH die set has no expander die?

[oley55]

(I'm particularly fascinated as to how the case expander/flare die wouldn't cure
any such anomaly no matter what.)

I'm not so fast or good at posting pics, but here some before after measurements.
sized case .368/.384". same case now measured after CH mouth expander .376/.394".

The remaining out of round forces me to over expand so I can seat a cast bullet without shaving, but also means more cracked case mouths.

Are you saying the CH die set has no expander die?

no I was responding to expander ball, which is what my bottle neck sizing dies have. yes my CH set has an expander die, but I usually use a Lee M die.

[TimSr]

What is a "CH" die?

If after resizing, you cases are not the right shape, then there is probably a problem with your resizing die. If its an older carbide die, it may have a carbide insert that has come loose or shifted, or maybe you have some kind of buildup in the die. I'm inclined to believe that the problem will go away with a new resizing die.

Do you have access to another die set to see if it solves your problem? I guess its possible to have brass hardened to the point of springing back after resizing, but I really doubt it.

[oley55]

CH actually a C with an H inside it. https://www.ch4d.com/home
https://www.ch4d.com/about-us


their sizing die has a pretty hefty carbide ring in comparison to Lee. nothing wrong with the die. If it was the die I believe every case run through it would come out with same or similar dimensions.

[reddog81]

Sounds like a new sizing die is needed. They can be found for cheap. It looks like there is a C & H sizing die on ebay with buy it now price of $15 plus $4 shipping. You could probably post a WTB ad and get one for cheap. Heck, I'm sure I have an extra steel sizing die if you want to pay postage...

[reddog81]

Oops, it looks like you posted while i was typing...

If die produces good brass sometimes and bad brass sometimes that is a conundrum... Are the cases from a variety of guns? Could one of your cylinders be out of spec and causing the brass to expand larger than it should.

[dahermit]

I would suspect uneven annealing (although you did not mention ever annealing the cases), if they have ever been annealed, that is. Soft on one side, harder on the other. Have you ever attempted to anneal those cases?

[oley55]

most recently they have been coming out of a Rossi R92, and well Rossi chambers are Rossi chambers, but then isn't that why we size cases, to correct/return to spec dimensions.

No, never been annealed. But, since I do pin wash/tumble my brass, I dry by spreading them out on a dark towel in the sun. They do get hot enough from the Florida sun that they are too hot to handle by hand. But I do not see how that could ever be hot enough to partially anneal one side.

I have some new (once fired) Rem brass and I am not seeing the oval mouth problem. So these older brass cases must be work hardened and not accepting a complete resize. Have no idea how to try and anneal these relatively short straight wall cases. may just have to bite the bullet and buy new brass

[YARDDOG(1)]

I use Lee dies & resized 357 mag cases ove 15 times still going strong. They are on the mild side, No problems ; )
Y/D

[Unclenick]

…sized case .368/.384". same case now measured after CH mouth expander .376/.394".

So, basically the brass springs back to the oval shape after expanding. No surprise there. The question is, was it oval before resizing? If so, and assuming the stress causing that oval shape has not been relieved, this is no surprise, either. You can try annealing the upper half of the case, but be careful not to let the head get hot, as this weakens the brass.

It is possible the Rossi chamber is oval with the long axis vertical to promote feeding. Fire some ammo in that gun and see if the brass comes out oval like that. If so, it's the Rossi chamber.

[44 AMP]

Have no idea how to try and anneal these relatively short straight wall cases.

If you know how to anneal the cases, what would be the problem??

The old time method is to use a torch, and an old cookie tray or other similar shallow pan. Set the cases on their bases, add water to cover the case heads and a bit more, then anneal. The water will act as a heat sink enough that the case heads won't get hot enough to get soft. A propane torch lets you direct the heat only to the necks.

[mannyCA]

Toss those old Western head stamped brass away already!

But seriously.
I can understand frugality but just get a new lee FL die, they're well worth the money and will last you another 20 or so years.

Oh and if you really want concentric brass during sizing you can do a quarter turn on your brass after the initial sizing and run it back through. This works really well on rifle brass.