Look at this case and tell me whaddup....

[Revoman]

I went shooting today as is my usual Saturday morning ritual, and had reloaded 200-40 cal to do some practice work rapid fire for an ICORE event next month.

My load was 155gr LSWC from Bear Creek over 5.1gr of WW231, WSP and WW case once-fired case (range pick up).

Out of the 200 rounds that I fired, within about the first 40, I had this case to ponder about and see if another found it's way. No others did.

All of these rounds were fired in a 610-1 revolver....no ill effects at all and no extra 'power' noted, nor low power. All of the rounds fired seemed to be the same as far as recoil etc. (I wear electronic ears and noted nothing special.)

Thoughts on what might have caused this?

[EmmaGoldman]

You stepped on it after ejecting or... ?

[toby]

That happened after you ejected the case's, no way could that happen in a chamber, and it most certainly would not have come out easily.

[Black_Talon]

What they said^^^^

Are you sure it's even your brass? Maybe it's one that was already laying on the ground?

[Sub95]

he was shooting out of a revolver and doubt he just drop his cases on the ground, i could be wrong though?.

Now it looks like it got super hot and folded in, by the grayish look to the outside of the case. i would say its just a bad case.

[toby]

Almost looks like it was hit with a bullet while laying out in the range and someone kicked or tossed it to the firing line???

[diginit]

Wow. The case obviously folded during ignition... Due to the powder burn on the fold. Usually they just crack. I'm wondering is ammonia was used in the tumbling... That case is very weak from fatigue or from something that weakens brass. You're lucky the casehead didn't seperate from the case. What do you add to your media to clean and polish your cases?

[TKM]

Originally Posted by diginit

Wow. The case obviously folded during ignition... Due to the powder burn on the fold. Usually they just crack. I'm wondering is ammonia was used in the tumbling... That case is very weak from fatigue or from something that weakens brass. You're lucky the casehead didn't seperate from the case. What do you add to your media to clean and polish your cases?

Plausible.

Got me scratching my head though. I've never seen anything like that happen in a revolver but thanks to the intertubes I see new stuff everyday.

[EmmaGoldman]

looking again, the one other thing I can come up with is this:

While loading the ammo, the bullet caught the top edge of the case while being seated and scrunched it down a little. This problem was not noticed between loading and firing. When the cartridge was fired, most of the case sealed against the chamber wall, as is usual. The wrinkled portion of the case mouth did not seal against the chamber because of the wrinkle and pressure pushed the wrinkled section back in to the case.

I have a hard time imagining how there would be a pressure differential between the outside and inside of the case to allow the movement, but it's the best I can come up with.

[diginit]

Originally Posted by EmmaGoldman

looking again, the one other thing I can come up with is this:

While loading the ammo, the bullet caught the top edge of the case while being seated and scrunched it down a little. This problem was not noticed between loading and firing. When the cartridge was fired, most of the case sealed against the chamber wall, as is usual. The wrinkled portion of the case mouth did not seal against the chamber because of the wrinkle and pressure pushed the wrinkled section back in to the case.

I have a hard time imagining how there would be a pressure differential between the outside and inside of the case to allow the movement, but it's the best I can come up with.

I was thinking the case could have been folded during seating also, But I think the powder burn would have been on the inside of the fold and forced it into the chamber wall straighting it out and reconforming it to the cylinder wall, rather that the burning it on the outside and forcing it down...Somehow, The gas didn't expand and seal the case to the wall and bent it inwards instead. Wierd...Strange things happen under pressure. I once had a round stand up in the bottom of a weak 1911 mag and the follower set it off under recoil of the next round fired. Gremlins seem to be hard at work.

[diginit]

I just noticed "Range pickup"... There is no way to tell if it was once fired or cleaned with an ammonia based cleaner and reloaded by someone that didn't know ammonia weakens brass. For all we know, It could have been cleaned with Windex or fired 50 times. There's the problem.

[eaglemike]

You might want to chrono that load, my friend. Pretty sure it's way over needed pf.

The case damage wasn't caused by that though.......

For those that don't know, shooting .40 in a 610 requires a moonclip. The case isn't long enough to headspace normally....

[sammy]

Compare the firing pin marks with the other cases. I am willing to bet this did not come from your pistol.

[Revoman]

Revolver, yes.

It was not stepped on as it came out of the cylinder still in the moonclip.

Extraction was not an issue.

I use walnut media mixed with a cap full of Nu-Finish.

"While loading the ammo, the bullet caught the top edge of the case while being seated and scrunched it down a little. This problem was not noticed between loading and firing. When the cartridge was fired, most of the case sealed against the chamber wall, as is usual. The wrinkled portion of the case mouth did not seal against the chamber because of the wrinkle and pressure pushed the wrinkled section back in to the case.

I have a hard time imagining how there would be a pressure differential between the outside and inside of the case to allow the movement, but it's the best I can come up with."

This is plausible, I check my loads pretty closely, but I'm not perfect and could have missed one for sure.

I am baffled to say the least.

[SandDiegoDuner]

Could it be possible that you had the neighboring cylinder fire just slightly off center and the gas reflected back pushing the case wall inward? I looks like it has a lot of soot on that portion of the brass. I don't shoot wheel guns so just a thought...