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biglou13

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9 mm

Had a case blow up. Just above rim. Not a case separation, just blew out a hole, damaged next bullet in mag. Nothing catastrophic? No injuries no damage to gun thank God.

I've read where this can happen albeit a very very rare situation.

I think I may have let an over crimped cartridge get in. Just set up Dillon 4th die. I'm pretty religious with my reloading technique, I'm 99.99999 % sure it was not a double throw.

But it got me thinking....

Other than weak case what else could be problem?

I will only buy once fired brass from this point forward. Aka from. Military or police range... At least these are known number of uses.

How many of you had experienced some kind of case failure? / KB

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Overcrimping wouldn't cause it. If you are so certain it wasn't a double charge then probably was bullet setback. I guess it could have just been a weak case but not likely. I load 9MAJOR over and over and over. Cases generally split or primer pockets get loose first.

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I've seen friends plenty of split cases.

Are you saying over crimp would NOT cause over pressure situation?

When set back. Do you mean bullet is pushed deeper into case?

Unfortunately friend was shooting gun.... I know what a double throw feels like..,.. So I'm not 100% sure on double load. I've only had one, from first day on Dillon.

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What bullet and powder were you using?

I load 9mm Major, and had this happen three times to me - all

within a few weeks (I've been loading 9mm Major for 8 years).

Just got my TruBor back from gunsmith - he replaced springs,

etc, and of the first 1,000 rounds I fired, three blew holes in

the cases (split them above the rim) - at least two were WW

cases - not sure what the third was.

Never found out what the problem was, but it has NOT

recurred in the past three years. :cheers:

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I've seen friends plenty of split cases.

Are you saying over crimp would NOT cause over pressure situation?

When set back. Do you mean bullet is pushed deeper into case?

Unfortunately friend was shooting gun.... I know what a double throw feels like..,.. So I'm not 100% sure on double load. I've only had one, from first day on Dillon.

No, over crimping would not cause pressure. I mean, maybe if you crimped 1/8" into the bullet so it couldn't move possibly but that's not gonna happen on a reloading press.

Yes, setback is when bullet gets shoved into case further and radically increases pressure.

Ironically, too much crimp could lessen neck tension and cause setback. So I guess technically too much crimp could cause pressure issues in a roundabout way.

Edited by Sarge
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OP, you had a case rupture, not a KB. If it KaBoomed, it would have split the barrel, cracked the slide and frame and blown out a bunch of internals, plus most likely you would take a frag. I have witnessed several KaBooms, which resulted in mild to severe injuries***, and I had a case rupture on my G34, years ago, from bullet setback, verified by inspecting the remaining 300 rounds, 12 were short by more than .060" So what loader, bullet, powder charge, and OAL? This was from a recent USPSA match where the guy was running an open gun. He believes, but could not verify, it was once fired. No injuries to the shooter, but it did blow the mag apart. And because were the good guys, he got a reshoot.

*** Shooter blew up a G21 with factory ammo on a table start. Fragments bounced off the table top and one piece went up his nose, the other thru his open mouth. Both frags could not be removed by surgery due to the proximity of nerves. Fortunately the RO had just told him to put his safety glasses on before the beep, and a fragment was found embeded in the left lense. Measured the OAL on the remaining rounds, and then pulled the bullets and weighed each charge. It was bullet setback on 3 of the rounds out of 50 in the box.

image37150.jpg

Edited by 9x45
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Indeed, not a KB, just a benign rupture, I had dozens of them.

Almost ALL of them in my case happened to Winchester brass, I would say 95% of them.

Usually you just get a puff of smoke into your face, not more drama. In rare cases it might blow the magazine out, but that is very rare.

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"Once fired brass" is a wonderful sales tool, but, unless you make it once fired from factory ammo or new brass it is impossible to tell.

Yeah you couldn't be more right. I have purchased once fired from several different places that had brass fired more than once. At least had been chambered more than once from the extraction marks on the case.

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well they know is is fired at least once.

the implied that is was only fired once is amusing.

the conclusion is another thread was that once you eliminate

all the usual suspects it leaves the case failed.

make sure you don't have bullet set-back

and if you are confident the powder was not doubled

and the other impossible things like firing out of battery and unsupported chambers

are not the cause.

it leaves only a tired and weak case.

to reinforce the WIN bashing a bit.

in my cleaning and processing I found a win headstamp with a

32nd inch hole burned through rather near the extraction groove.

kinda an eye opener... I did not take a picture.

I recently traded my scrap for a few more cases...

while I think it is gone, I'll look a bit anyway..

didn't think much about it at the time.

I doubt I'd have noticed if I had not polished/tumbled the brass.

miranda

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