Steve,
That particular post was directed toward Steve692.
Would love to hear if you have evidence that Hatcher was wrong about primer appearance. None of the piezo-lab people I've talk to believe he was, for the reasons stated in my article: There are too many variables in primer cups, and other factors such as headspace, bolt-face, etc., for primer appearance to work even as a rough "estimate" of pressure.
Which is why I ran experiments on such traditional pressure signs with the help of one of those piezo labs over 15 years ago. One .270 load averaged around 69,000 PSI, with some of the individual shots over 70,000. Yet the primers appeared completely "normal," just as normal as the primers used in a .30-06 load that averaged 58,000 PSI.
In fact the only "pressure sign" that followed the piezo results was velocity.
