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Old April 12, 2009, 01:21 AM   #1
Sixer
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Split case (pic)

Got out to the range this weekend to try out some loads I worked up for my .30 Carbine. Everything went smooth, and my groups were actually pretty good I was shooting 110gr Sierra soft point JRN bullets with 14.8gr of IMR-4227. I popped off about 30rds total and had no issues.

The brass I have was bought from a friend. He was pretty sure that most of it was once fired brass, but mentioned that some of the cases may have been reloaded more than once. Anyhow, I noticed this little fella with the crack in it shortly after I picked up the last few remaining cases...



Just curious if anyone can tell me if this was most likely caused by too much pressure, too much powder, just an older case, or something else??? Thanks!

ETA: The crack goes about half way around the case.
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Old April 12, 2009, 06:23 AM   #2
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Can't tell from just that one pic. Looks like metal fatigue. What does the base look like?
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Old April 12, 2009, 08:05 AM   #3
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Quote:
...Looks like metal fatigue...
Did you mean, "work hardened"?
Brass becomes harder the more it is worked. However, work hardening cracks usually start at the mouth of the case and run longitudinally. Nevertheless, it does look like the result of hard brass...suggesting that the case had been reloaded several times.
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Old April 12, 2009, 08:43 AM   #4
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I've seen brand spanking new cases do that.

I've always called it burn through, and figure it's either a weak section of the brass caused by an impurity or some other structural flaw.

It's usually isolated to a single case in a batch and is of no cause for concern.
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Old April 12, 2009, 09:15 AM   #5
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Mike Irwin,,, don’t mean to sound like I disagree with you because I don’t, but I have been reloading 30 carbine and other military rifles for many years and I have never seen the like. I have had a case head separation once but that was at the pressure point closer to the base of the case.
My question is, have you ever taken one like it apart, and is there a thickness difference at the point of the crack?
Can’t really tell from the photo but it looks like it could be where the base of the bullet would have been.
Also Sixer,,, was the photo taken before or after cleaning?
Do those small circular lines that go around the case at the mouth look like stretch marks, or could it be a chamber that’s rough causing the stress?

Last edited by Ozzieman; April 12, 2009 at 09:22 AM.
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Old April 12, 2009, 10:29 AM   #6
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I've seen 1 .357 case do that. also 1 .380acp. I suspect both had been fired several times.
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Old April 12, 2009, 01:25 PM   #7
Mike Irwin
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I've had .32, .38, .45, and .357 Mag. cases do that over the years, perhaps a handful.

I've never sectioned one, but just from appearances sake it does appear that the brass has been thinned considerably around the margins of the crack in the ones I've looked closely at.


Now that you mention it, it has only ever happened for me with straight walled cases. I don't know why.
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Old April 12, 2009, 04:48 PM   #8
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Thanks for the input guys. Ozzie, I did wipe the case with an oily rag before I took the pic. I was thinking the same thing regarding the location of the base of the bullet... Not sure if it's normal or not, but all of my 30 carbine reloads do bulge slightly right around where the bullets base is seated.

With that being said, I'm thinking the brass was probably fired more than once. The seated bullet likely stretched the case a tiny bit, further weakening the area. This combonation resulted in the brass splitting where it did...

I just wanted to make sure this wasn't an issue of overloading. I've worked up quite a few reloads and don't really want to pull all the bullets, dump the powder, etc...
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Old April 12, 2009, 06:00 PM   #9
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Do the primers show any pressure?
I would inspect the chamber real close also.
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Old April 13, 2009, 06:37 AM   #10
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Looks to me like a case that had been cleaned using an ammoniated cleaning compound. The brass appears normal but after some time, it will crack or whenever it is worked it will crack. Apparantly the ammonia causes the brass to become brittle and the least amount of working causes failure.
I had a batch of 30-06 brass for my Garand that had the same problem. I ditched the lot of them. (They'd been cleaned in Brasso)

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Old April 13, 2009, 12:20 PM   #11
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Again, thanks for the input fellas... I know it's hard to determine with the amount of info I've provided.

To answer a few things... The primer showed no signs of excessive pressure, and the brass has only been cleaned in a vibratory tumbler w/ a bit of Flitz (at least since I've had it). I also checked the chamber, and as far as I can tell it looks fine

I think I'm gonna chalk this one up as one bad case in the batch.
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