9mm cases splitting

[John McCorkle]

Hi all

I've reloaded 9mm for a while with boolits and am only now taking the advice of so many here and using a larger expander that reaches deeper into the case body to make sure the boolit isn't swaged while loading... hoping to see good results but it's seems a good practice for cast boolits with many/most having great success.

I'm noticing several split cases in this operation (doing these on a single stage press at the time just to get a feel for it and glad I am...I can absolutely feel when they split) using Lee does with a 38sw powder through expander I polished up the mouth just a touch with 1000 grit followed by strop paste to really smooth/polish it up but didn't take any off the diameter of the expander stem when doing so.

I know brass has a lifespan and I'm certain the cases splitting aren't on their first reloading...but wanted to poll you all to see if you guys are seeing the same thing?

Getting splits on 1-2 out of 100...not a ton and I've got a ton of 9mm sonit isn't causing a problem per se but I found it interesting, never seen this in 9mm at this rate. I know it is due to the larger and deeper expansion but curious of your experience with this?

Sample of cases below...I guess I've expanded 2k by now so I'm seeing a pattern

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[tazman]

Interesting. I don't believe I have ever split a 9mm case during reloading.

[Walks]

Me neither, weird.

I use a 45yr old Lyman Die set with a
M-Expander die with a .3555 insert. The sizer is a 1980 Carbide with a C&H taper crimp die from about 1984.

I use Lyman #356402 or Lee # 356-125-2R
sized to .356dia, never had a split case that I can recall.
Shooting this ammo in Walther P-4, P-38, 1921 Commercial Luger, Browning Hi-Power, Glocks with Wolf bbl's and Ruger 9mm cylinders.
Loaded over max Bullseye.

I've also shot it in Sigs, S&W's, Beretta's, Colt AR's, Marlin Camp 9's and a bunch of others that I can't remember.

I only use American Commercial or G.I. cases and a few Fiocchi.

Never range pickup. Those I just sell when I have enough to make it worth while.

[unclemikeinct]

Be thankful those split before loading/firing. I've lost 3, 9mm cases in forty years of reloading. When they split on firing. it is not pleasant. I have never had a 38 special behave like that.

[ioon44]

Are all the split cases the same head stamp?

[John McCorkle]

Be thankful those split before loading/firing. I've lost 3, 9mm cases in forty years of reloading. When they split on firing. it is not pleasant. I have never had a 38 special behave like that.

I've seen them split in firing before but it's typically a small fissure on the side maybe 1/8th below the mouth and about a 1/16th long. When it's a crack in firing it's shown carbon scoring in an hour Glass shape in relation to the crack as the gasses vent but it's never harmed the gun that I know of...it's a bit louder and can't be good for the chamber but never seen any negative effect

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[John McCorkle]

Are all the split cases the same head stamp?

No it's all over the place, Speer, Winchester, sig, Remington Federal...all of em. Wish there were a pattern

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[Bashby]

I split a few during my last session. I am using a 38sw expander in Lee dies also. IIRC, I had it set pretty deep.

[toallmy]

I use a lee 38 S&W powder through expander plug and don't have that problem , or at least not yet .

[hermans]

John, do you have access to a micrometer? If you could measure the size of your expander plug, maybe that can shed some light on the problem?

[RydForLyf]

Very interesting. I'm looking forward to how this turns out.

[John McCorkle]

John, do you have access to a micrometer? If you could measure the size of your expander plug, maybe that can shed some light on the problem?

Looks like a .3568-357 ish

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[John McCorkle]

John, do you have access to a micrometer? If you could measure the size of your expander plug, maybe that can shed some light on the problem?

Also this, this AM I am processing through a batch of 9mm that was previously expanded with the original plug (original Lee 9mm powder through expander - I pre prepped alot of brass in stages)

These have yet to give me a split...I've only expanded a couple hundred so sample size is small and not ready to say it's not giving me any problem period....but it's interesting

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[Burnt Fingers]

Wow! That's not a split, that's a tear.

I've found a few split cases while reloading. Not many 9mm, mostly .45 ACP. It's always a small vertical crack at the case mouth.

Something is going on in your process. Try some Hornady One Shot sprayed into the case mouth.

[John McCorkle]

Wow! That's not a split, that's a tear.

I've found a few split cases while reloading. Not many 9mm, mostly .45 ACP. It's always a small vertical crack at the case mouth.

Something is going on in your process. Try some Hornady One Shot sprayed into the case mouth.

Sort of what I thought, it's surprising and I've never seen anything like it before. I haven't heard others who have either.

I think I could prob use one shot or any number of lubes but I don't think others here do/have and I'd like to not make 9mm an even more pia than it is especially when loading in bulk.

My real concern is that with this issue popping up I don't think I can reload on a progressive press at all...

Would love to find that root cause you mentioned

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[Dusty Bannister]

Is the new expander plug as well polished as the original? Is it too loose or not centered in the die body? Maybe too sharp on the end of the plug so it does not enter the case mouth smoothly?

[Murphy]

I've been reloading nearly 40 years and that's a new one to me. I don't believe it's a case problem. I'm not sure how deep your expander is set, but that would be my first suspect. Please keep us informed when you discover the problem. It will be interesting to know what is causing it.

Murphy

[JonB_in_Glencoe]

Have you measured case length of the split/torn cases?

[John McCorkle]

Is the new expander plug as well polished as the original? Is it too loose or not centered in the die body? Maybe too sharp on the end of the plug so it does not enter the case mouth smoothly?

So originally when I first got the plug the "feel" of it was very sharp... meaning, entering the sized brass case mouth would result in a snag fairly often ...so I took it out and slightly reprofiled the leading edge of the expander with 1000grit...may not have actually reprofiled it at all it but that was my intention...then hit it with a polishing compound that makes it very very smooth. What was and still isn't polished well is the body/shaft of the expander stem and I can feel the tooling marks on the stem as the cases slide onto and off the expander...again all of this is by feel but I can definitely tell

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[John McCorkle]

Have you measured case length of the split/torn cases?

No but not sure I would get a consistent read with the amount of tear/rupture on them after they split

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