.....from reading (and rereading) a manual, and not just the load data! From Speer #10, 1979 edition, I was doing some casual reading on the 9mm and came across this..... "There is considerable variation in case mouth thickness and between brands and lots of cases. All must be sized to hold bullets very tightly and the expander ball should not exceed .354" in diameter. Because this cartridge headspaces on the case mouth, very little crimp can be used. But MOST IMPORTANT, loads that produced 28,000 cup went to 62.000 cup when bullets were purposely seated .030" deeper!. Thus, it is of the utmost importance that bullets do not become deeper seated in the feeding cycle." "Pressures of the maximum loads shown do not exceed 35,700 cup, the maximum industry working pressure." Thought this might be of interest. Cheers!