Case rupture

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DKJ

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Okay, I have a Dillon 650 and am reloading 9mm.
I'm using Win 231, my Hornady book shows max load for a 124 gr FMJ at 5.2 grains of powder. I've been using 4.5 grains of powder and have shot off several hundred rounds with no issue's till today when I had one casing that split. When I load I visually inspect each round to ensure no overcharging is taking place. This was once fired American Eagle brass, I made sure my OAL was proper and there was no other indication of overpressure coming from any other rounds. The headstamp was still fresh with no flattening.
Any ideas as to what happened here? Was this a one off, bad casing, or something else taking place?
 
Throw it on the scrap bin and carry on just like you have been. Brass does not last for ever. Could be a one off, small defect in the case. Your loads are reasonable and as long the your powder thrower is consistant, you are good to go.
 
If your running your 650 with the powder rod on the thrower I can't see a double charge.... If your press is mounted to a table that moves around a lot or you have the bad habit of tapping on the powder hopper then any powder left in the charge bar and hopper will settle and compress throwing an out of spec charge or two when you start loading.

My money is on a bad piece of brass tho... It happens...
 
i've had 22's that the case split, just happens.

it's hard to keep track of brass in a semi auto for number of firings, but i've reloaded my 357mag brass 4-5 times now. have yet to see any cracks.
 
DKJ said:
Okay, I have a Dillon 650 and am reloading 9mm.
I'm using Win 231, my Hornady book shows max load for a 124 gr FMJ at 5.2 grains of powder. I've been using 4.5 grains of powder and have shot off several hundred rounds with no issue's till today when I had one casing that split. When I load I visually inspect each round to ensure no overcharging is taking place. This was once fired American Eagle brass, I made sure my OAL was proper and there was no other indication of overpressure coming from any other rounds. The headstamp was still fresh with no flattening.
Any ideas as to what happened here? Was this a one off, bad casing, or something else taking place?
Click to expand...

Did the case split near the neck or rupture back near the head of the case?

Graydog
 
Toss it in the trash. Out of every 1000 brass I reload, about 2-4 will be cracked after the next firing due to them wearing out. I don't keep track of how many times I load them either for my bulk plinking loads, which doesn't help, but it is a non issue.

Chuck it and move on.
 
Some guns seem to be harder on brass than others. I loaded some lead 9mm 135's for my P30L and about 15% of the cases split. The same load in my Sig226 has no problems at all.
 
Sometimes you just get a bad lot of brass (Norinco comes to mind on some 45 ACP brass) - learn to recognize the bell like sound as you handle the shot brass that indicates a split case.
 
I had about 1K of 9mm reloads that were part of a trade. Almost every case split in the first 20 or so rounds. I pulled some bullets and used needle-nose pliers to perform a little torture test and compared the results to some brass from another source. Every piece of the old stuff seemed brittle and tore very easily. I scrapped it all. Best theory that I've heard is that the brass may have been cleaned with something that contained ammonia (brasso?), and that may have affected the metallurgy of the brass. Just about wore out my bullet puller!
 
One other thing to watch for is how much bell/flare you use. A little too much flare will over stretch the case mouth and cause the start of a crack. You might not be able to even see it but when you shoot the tiny flaw turns into a full out split. I had a problem like this with a whole batch of reloads, ruined a few hundred cases until I figured out the problem.
 
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