Re: Is this excessive pressure???
Are you measuring across the web or the casehead itself?
The belt on my 416wby will start at .602" and go to .605" with virgin brass. They will go to .606-7" if the loads are near max. If loads are kept at what caused expansion to go to .605", it never gets larger.
With what causes them to go to .607", the next load will go .608" and so on, until they are hard to extract at what seems to be a couple more reloads. After I check this on the Oehler 43 I'll know what PSI is doing what.