High Pressure? (with pics)

[Mike Irwin]

"i bought this lot of cases brand new. Lot of 50. They have never been cleaned. I opened the box, ran them all through my redding FL resisizing die, trimmed, uniformed primer pockets, charged with about 3 week old powder, and seated my bullet without a crimp."

Exactly. I've had numerous similar mid-body splits with BOTH brand spanking new AND brass that has been fired and reloaded many times.

The cause is a weak point in the brass that fails.

Cartridge brass isn't perfect. The manufacturing process isn't perfect. The reloading process isn't perfect.

Yes, there is evidence of gas leaking out of the crack and into the chamber because that's exactly what happened.

The high-pressure gas pushing out of the cracked area overcomes the resistance of the brass being pushed against the chamber walls.

My guess, though, is that it doesn't happen at the start of the ignition cycle, when chamber pressure is rising, but AFTER peak pressure, when the brass begins to contract away from the chamber walls.

[insco3]

Thanks Mike Irwin

Makes sense to me.

This would explain why the cases are cleaner than F. Guffey would like to see.


Insco3

[F. Guffey]

This would explain why the cases are cleaner than F. Guffey would like to see.

Again, I do not want anything between my chamber and case but air, I do not want a lot of air, that is the reason I size my cases to fit the chamber. And then there is clean air, the air I have between the chamber and case must be clean because the case is embeddable. And then there is time, I understand slow burning powder is cute but there is a limit, if the powder burns too slow there is a chance the case neck will not seal the chamber; when the neck does not seal hot high pressure can leak back and past the neck and then get trapped between the case neck and case head. I understand that does not present a problem for anyone else but it does for me when the pressure drops inside the case.

I have absolutely no interest in firing cases that split the case body, I have loaded rounds that will split the case body 4 out of 10 rounds, everyone of the splits will blacken the case body and chamber. I can prevent the splits by busting up the clods and changing the cases and primers. I could pull the bullets, bust the clods and then reseat the bullet but, again, I would still have Berdan Primers.

Any how; anything between the case and chamber when fired will be embedded into the case and again I am the fan of having nothing between the case and chamber but clean air.

F. Guffey

[F. Guffey]

The cause is a weak point in the brass that fails.

A snith that was set up at the Market Hall gun show had one of his customers accuse him of building a custom rifle that had all kinds of head space problems, the smith told him to bring it to his shop, and then he examined the case.

I did not get involved, I waited until they had finished and the man with the defuk rifle made a it to me. I asked him to show me the case from the rifle with 'bad head space'; he did. I examined the case and asked the proud owner if that was the only case he had for this wildcat chamber? I asked him is he was shooting and reloading that one case over and over and over and over? I told him that case was so thing it would have trouble standing up straight without support. The builder/smith came down to examine the case again and then suggested the case be examined by a third party. The rifle owner was instructed not to tell the third party examiner what I said and he was told not to tell the third party who build the rifle.

Off he went to a smith of few words: The smith took the case, ripped it apart and measure the thickness of the case body; the thickness of the case was .002", the smith informed the proud owner .002" is a good thickness for paper but not for a case that has to be sized and ejected after firing.

To split a case body there has to be something else going on besides a defect. I could not believe the reloader loaded those cases so may times the case was so thin it would not stand up straight. I offered to form 200 cases for free from new/never fired cases and I promised him I would form the cases with .002" clearance but when he left he was not speaking to me and he did not return to the gun shop with the rifle.

F. Guffey