Encoredude,
You can get a gunsmith to open it up to a larger bolt face or you might stumble on a bolt for sale. But, it that is what you want, it might be better to find an XP that originally had that .473 bolt face. Once you achieve that, by modification or trading, you could have any wildcat or factory cartridge built with the same base as the 30-'06. I remember a guy that had his 7 BR recambered to .284 Win. He used it for Handgun Silhouette at rifle ranges. Of course, now you have lost the capability to use the .223 case family. IMHO, if you build a heavy thumper you will NEED to get a different grip. That factory grip is ok with a 221, 223 or 7 BR but, with larger cartridges, it hammers the top of your hand.
Congratulations on the XP. Does that make you the XEncoreDude?
A17Shooter