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

[LRRPF52]

Thank you for that dimension. Just using your numbers, I get .138" - .133" = 0.005" difference. And so if I understand your position correctly, you are saying that, in this scenario, the OPs casing was roughly 0.005" more unsupported, and possibly more if you add headspace. And this distance is what is considered dangerously excessive?

To me, for sure, it's on the table still but I could still see this issue as being additive on top of a brass and feed cone depth issue. And because the dimension of feed cone depth looks to be larger than 0.005", then I personally would not rule it out.

I’m not following those numbers. I’m not sure what you’re saying, so it might just be me.

The deeper the bolt face, the longer the headspace.

Grendel bolts should be no deeper than .136”, but can be .003” shallower (.133”). Chambering will be more difficult and not repeatable under some conditions if you go less than .133”.

Chambering will be easier with deeper than .136” (out of spec), but then the case web won’t be supported and you can have things like this.

Most bolts I’ve measured were either .136” or .135”, but I do recall one that was .137” that probably shouldn’t have left the vendor.

Once you start exceeding the dimensions, tolerance stacking can occur and create unsafe headspace.