.204 acceptable case head expansion

[moorepower]

As the title says, what would be considered acceptable case head expansion, measuring the ring at the base.

 

[drover]

I am assuming you are asking the question because you are handloading.
If you have a factory loaded round measure the ring at the base, fire it then measure the expansion, use that measurement as your acceptable case head expansion.

drover

 

[RegionRat]

The max dia at the 200 line is shown at 0.3759" on the cartridge, and 0.3788" on the chamber.

Those are the extreme values on the SAAMI specs, but who is to say.

The likelihood of a chamber at max diameter isn't something I could guess, but I would say that a value for the brass occurs when the primer pocket won't hold, regardless of what those specs say.

 

[moorepower]

I am assuming you are asking the question because you are handloading.
If you have a factory loaded round measure the ring at the base, fire it then measure the expansion, use that measurement as your acceptable case head expansion.

drover

 

[moorepower]

Yes, I handload. Some of my Norma brass has a more noted expansion than others. I thought that I have read what the normal expansion was, but I can't remember where. It on the first firing of the brass.