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

[lazyengineer]

Once again the thin vs. thick brass assumption creeps back in. There is nothing 'appears' about it - it is pure speculation. We do not know the relative strengths of Hornady vs. Lapua. We may never know what caused that case to burst.

It never creeped out - and there is no speculation- it's staring us in the face, and the heavily quoted Alexander confirms that a chamber dimension needs to be just so with that brass. Walls don't hold pressure, they are a gasket. Case heads hold pressure. No case head where there is no chamber wall = not holding pressure.