Okay. I am stumped. A Savage .270, in new condition. Using Fatory ammo.
A round broke the extractor and the suspect case had a CRATERED primer. The primer was pushed in! I have been reloading and learning for over 30 years. I have never heard of such a thing and can't explain what happened. The owner of the gun said the ammo manufacturer said it was an over loaded cartridge. If so how can the primer be CRATERED? The gun was sent back to the manufacturer for inspection. I was just wondering if any of you have come across this malady? High pressure flattenes primers. I thought. What in the world craters them?

It's true, high pressure flattens primers.

By cratering, I assume you mean a small rim of raised metal around the firing pin indentation. There is a small space around where the firing pin comes through the hole in the receiver. At higher pressures than what flattens primers, the metal of the primer starts extruding into this space creating a rim of metal. Push the load further, and you get pierced primers or primer leaks.

Yes. That is a typical senario of high pressure or an enlarged firing pin hole. What happened to this particular rifle was the primer was cupped inward, cratered. There was no case rupture. Could the primer pocket have expanded enough for the gases to leak out around the primer and the resulting gases force the primer back in?

If gas escaped around the primer you would see soot around it and most of the time gas will cut a circular groove on the bolt face. This escaping gas will exit from the gas relief holes and firing pin hole and won't push the primer in like you describe.
You didn't explain how the extractor broke! They are not much in a Savage, just a spring clip. I suspect the case was stuck and the force used to open the bolt broke it rather then gas pressure breaking it.
I can't explain the look of the primer though. Pressure can do some strange things.

I have overloaded Mauser and got a stuck case.

If I jump on the rifle like a pogo stick, with my boot on the bolt handle, maybe it will come free.

Sometimes that doesn't work, so I throw the rifle like a spear, hitting the bolt handle on the shooting bench.

Sometimes that doesn't work, and I hit the bolt handle with a hammer until the bolt handle broke off at the weld.

If all else fails with a stuck case, take the barrel off.

If the brass got welded to the bolt face, cut it off with a lathe.

I have never broken a Mauser extractor, but if I did with factory ammo, it would most likeley be with a 270.

If the chamber is rough, the brass can get a better grip on the chamber.

Extractors can be weak and ready to fail with the stickiest case that comes along.

tnekkcc?:

I'm gonna dodge you on that one!!!

Sounds like you need a better weldor to put that handle back on!!

George

quote:

Sometimes that doesn't work, and I hit the bolt handle with a hammer until the bolt handle broke off at the weld.

Another good reason to alter your bolt handles by FORGING instead of cutting the good one off and welding another one on.......

I got to see the brass in person and it was sooty around the primer and yes, the primer was caved in. The Savage bolt handle was not hard to lift after the shot, as my friend reports. Just a strange case of over pressure. Thanks for the input gentlemen.