Primers are no doubt the poorest of the traditional methods for estimating pressures, despite what some people claim. This has been well-known among knowledgeable handloaders for decades, and in fact Gen. Julian Hatcher stated they were basically irrelevant in HATCHER'S NOTEBOOK, which despite many technological changes since it was published in 1948. This because there are too many variables that can cause the supposed signs of high pressure, including flattening and cratering, that have no relationship to pressure. (Despite this, some "experts" continue to tour primer appearance as a reliable method.)
It is not "my" book max, it's Hornady's, and they're the people who developed the cartridge.
