So go buy a caliper.
I'm not sure if I should take this as well intentioned advice (if it was, then thank you) or an insult to my intelligence.
FYI, I do own a caliper (two actually), and a set of bullet comparators I use regularly. My comment was in regard to time consuming and tedious nature of readjusting the mouth expander and seater dies ever single time I switch from one cartridge to another. Since I often will take both .454 and .45 Colt loads to the range at the same time, it means that I have to readjust the dies TWICE for every reloading session.
As for consistancy, with I caliper I can get the dies adjusted to very close to what they were before (within .001"), but it takes a lot of time to do so given the non-precise nature of adjusting the dies via the lock collars, and it's never quite perfect. My comment was meant to illustrate the fact that if one has two sets of dies, one never has to mess with the settings unless something changes. Therefore, having a set of dies for both, while unnecessary, is beneficial as it saves time, hassle and improves the consistancy of ones loads from session to session without the headaches associated with trying to finely tweek the dies to get them back to exactly where you had them before.
Mike