When reloading a new to me bullet I\’ll find a similar bullet in my manual(s) and start a dummy at the book OAL. Make sure there is no flare left on the case and plunk test it. If necessary shorten the OAL .005\” and repeat plunk test.
I have had more problems with case gauges than I care to list, so, I shoot my handloads out of my gun\’s barrel and not a gauge, so I size my handloads to my guns. Works for me for 25+ years…