This is the reading the author got from flush contact on a new Forster die. The author advises against setting the die bottom flush against the shellholder and commencing to shucking cases. Most die makers provide that as instruction, and some say drop it down another quarter turn or so beyond that. That’s excessive. Author Zediker has rarely encountered dies that wouldn’t set back a case shoulder enough even when set to flush. The only way to fix that is to have a machine shop trim the die bottom.