Interesting split cases

Trekker · Jun 15, 2017

In sorting through the loose brass picked I picked up on my last trip to the range, I found two cases that have an interesting split. Rather than a splitting straight down the case wall as I would otherwise expect, one split travels diagonally around the case, and the other zig-zags. Fortunately, looking at the case heads I could see that neither of this 9mm's were ones I shot.

Any idea if this is normal, and what effect this would have on the firearm?

Seabee · Jun 15, 2017

What make is it? any signs of high pressure? Never saw one like that before. Its like it split from being brittle rather than anything else. I'll be watching this one.

Ken

Trekker · Jun 15, 2017

I think I have the cases down in my reloading room somewhere; I'll poke around and find them later this evening perhaps. Aside from pictures of the headstamps, is there any other details I should check for and post? I do not have a digital camera save what is on my phone, and I was slightly surprised the photos came out OK.

Magnumite · Jun 15, 2017

oversized chamber...work hardened brass perhaps...reactive substance contamination

j_h_smith · Jun 15, 2017

Are you sure they came from your firearm and not just volunteers that were picked up along with yours?

Trekker · Jun 15, 2017

j_h_smith said:
Are you sure they came from your firearm and not just volunteers that were picked up along with yours?

Trekker said:
Fortunately, looking at the case heads I could see that neither of this 9mm's were ones I shot.

While I will be reloading for 9mm eventually, in the meantime I am still working through my stash of perfecta 115gr that I bought cases of during that low price period ~2 years back. Since the headstamps of these two cases are not perfecta, I am quite sure that they did not come from my firearm, and am quite happy about that.

Jmorrismetal · Jun 15, 2017

I would say "not normal" never seen a zigzag or helical split case before in more than 30 years reloading and you have both.

Lots of radial and linear though.

Ironnewt · Jun 15, 2017

This is the problem with 'range pick ups' who knows how many times this brass was reloaded (if at all) and what it was shot out of. I tend to mark all my cases if I see that someone else is shooting the same caliber as I am.

Blacksmith101 · Jun 16, 2017

Trekker said:
I think I have the cases down in my reloading room somewhere; I'll poke around and find them later this evening perhaps. Aside from pictures of the headstamps, is there any other details I should check for and post? I do not have a digital camera save what is on my phone, and I was slightly surprised the photos came out OK.

Pressure signs are usually flattened primers, protruding primers, or primers extruding back into the firing pin hole. Also look for signs of case bulge from being fired in a gun with an unsupported chamber.

9mm Pressure signs:
https://www.google.com/search?q=9mm...jSy8HUAhXLdz4KHaGhBKkQ7AkIcQ&biw=1280&bih=563

Case bulge pictures:
https://www.google.com/search?q=9mm...SNy8HUAhXDej4KHQBAC0IQ7AkIUg&biw=1280&bih=563

Doctor_M · Jun 16, 2017

That is strange. My guess would be that it was brittle brass and probably was the result of a bad batch out of the manufacturer rather than reloading problems.... but that's just a guess.

sgt23preston · Jun 16, 2017

It's simply bad brass...

I've seen this condition before...

BUT to be sure try a box of new ammo from a different manufacturer...

Then check your brass when you go shooting then next time...

Biggfoot44 · Jun 16, 2017

Brittle brass.

Pinecone · Jun 16, 2017

Old brass. Brass work hardens from being expanded and resized.

Then, when fired, the expansion cracks the brass. I have seen some .45 ACP cases with unknown history do this.

Biggfoot44 · Jun 16, 2017

Or occasionally an off spec batch of brass ( the actual raw alloy, not the euphemism for ctg cases). The opposite is when the alloy is too soft, and sticky extraction.

Trekker · Jun 16, 2017

Examining the cases, I am personally leaning towards brittle brass. I do not see any indications of overpressure, case bulging, or stress lines.

I originally noted these two cases on the basis of sound even before taking a look at them. The sound given off when these case contact another case is distinctly different from other intact cases. At the time I had wondered if it was similar to a bell changing its tone after developing a split. Of course, metal hardness will also affect sound.

I am having some issues loading the photo, so I will just report now that the case stamp is marked "R-P" on both cases. I will try again at a later time to upload the photo of the headstamp/primer.

Trekker · Jun 17, 2017

Ok, trying the upload again.

LGood48 · Jun 17, 2017

j_h_smith said:
Are you sure they came from your firearm and not just volunteers that were picked up along with yours?

sgt23preston said:
It's simply bad brass...

I've seen this condition before...

BUT to be sure try a box of new ammo from a different manufacturer...

Then check your brass when you go shooting then next time...

Stated in his first post that the casings were not from his gun, but range pickup. I've seen the helical split before, but never a zig zag!

PowPow · Jun 17, 2017

Trekker said:
I am having some issues loading the photo, so I will just report now that the case stamp is marked "R-P" on both cases. I will try again at a later time to upload the photo of the headstamp/primer.

That is Remington (Remington-Peters) brass.

Doco Overboard · Jun 17, 2017

I wonder if they were tumbled with steel pins that scored the inside of the case and had some sort of chemical additive. Reminds me of scoring and cutting glass.

Uncle Duke · Jun 17, 2017

Something out of the norm made that brass brittle. I'm wondering about ammonia or similar exposure as a possible explanation.

Interesting split cases

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