Flat primers (9mm) likley pressure?

[IM_Lugger]

Don't know what the load was but I shot it couple years ago and didn't notice the primers till i went to pick up the brass. Any one shooting 9mm major have an idea what the pressure must've been to flatten primers like that?

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[thump_rrr]

I call that recycling bucket brass.

 

[Grawfr]

Don't know what the load was but I shot it couple years ago and didn't notice the primers till i went to pick up the brass. Any one shooting 9mm major have an idea what the pressure must've been to flatten primers like that?

There's really no way to know how much pressure caused it, but I think all sources would agree it's excessive pressure... worse is that you shot it a while ago, so you can't know which load it was.

 

[madcow]

Defiantly excessive

 

[billdick]

I've seen that with head space problems. The firing pin will push the cartridge ahead before the primers goes of then the round fires and the primer pushes out the back a little bit then the brass slides back in the chamber and crushes the primer. I have also seen it with excessive pressure.

 

[flange]

Actual handload or possibly winclean ?

 

[IM_Lugger]

My reloads for sure.

About the headspace issue, could be a factor. It was a pistol fitted with an mediocre aftermarket barrel.

 

[quinnbrian]

Just a little more pressure...and you could just put a new primer in...and start reloading again... :-O You had to of hear that one , when it went BANG!!

 

[Ganderite]

Any chance it was a Federal primer?

 

[billdick]

With the primer off center I would say head space and not pressure. If the primer was square it could be either.

 

[redruns]

Primer seating depth may have contributed.

 

[bigedp51]

Don't know what the load was but I shot it couple years ago and didn't notice the primers till i went to pick up the brass. Any one shooting 9mm major have an idea what the pressure must've been to flatten primers like that?

Measure the flattened primer case just above the extractor groove and compare it to a unfired case and fired cases with a normal looking primer.

A larger base diameter means higher pressures vs a normal base diameter and a flattened primer due to headspace/head clearance.

That being said, any time I had a flattened primer like yours It was from a "hot" load. And these came from errors/goofs with thrown charges and never when weighing powder.