I had a partial case head separation using a 1.8oz buffer

[stonehog]

The more I have thought about this since yesterday, the more I am wondering about the bolt face depth.

If you had an out-of-spec bolt face depth that exceeds .136”, and a properly-cut chamber, it could also cause this to happen.

The fact that your extractor is intact, there aren’t any ejector extrusion marks or extractor pocket ledge shearing, and primer has a nice dimple on it all point to a well-within normal chamber pressure.

The flat primer is often seen in excessive headspace, when the primer backs out and slams against the bolt face, followed by the case re-seating over it due to brass expansion.

I need to go look at your headspace measurements again.



Click-no-bang is a telltale sign of excess headspace.

Firing pin hits the primer, which just pushes the floating cartridge forward in the chamber without activating the primer.

I measured bolt face depths which came out to in-spec per comments:
Odin: .135
Monster: .136
PSA: .133

FWIW - I also measured the length and lock tooth depths. Currently looking for the spec on all this, but someone mentioned it earlier:
Odin: 2.798" - tooth .278"
Monster: 2.814" - tooth .279"
PSA: 2.798" - tooth .278"

Firing pin length: 3.27"