I guess you need to decide how bad you want to use it. If you really want to use it pull the barrel, I would save that by the way, and put a new barrel on copying the factory contour.
I would chamber in the same case head size so as not to permanently modify the rifle. I'd go with a 25-06 myself.
Cool to see several other guys on here with their fathers Ruger No. 1s. Here's a pic of my dad's 6mm Rem. with a 4 digit serial no. The one I just got back from Ruger getting rid of the salt wood.