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

[grayfox]

I don’t think we know the angle in deg, but might be able to measure the diameters at the breakpoints, IOW the inner, chamber diameter should be close to constant but the outer diameter of the innermost radiusing… smaller diameter I would infer that it’s cone is smaller. Larger dia would infer a deeper radius, if the cut angles are all equal. It’s 4 am, hope my brain is thinking straight.

edit to add, I don’t think it is correct to say lapua brass was weaker as we don’t know the alloys nor the yield strengths for any of the brasses, but it can be said that the brass is thinner so could be more susceptible to a hot gas failure. And the gas pressures for a carbine system vs rifle length system, a 12” will have most likely a clgs, pressures at unlock in clgs are higher than in a longer gas system.