I was under the impression he wanted to change "just" the barrel. I may have misunderstood.
Yes, with that action length, he has a number of options in .473" cartridges alone, and if he were to include modifying the boltface, pretty much all of the cases based on the .458 WinMag become available.
I've done this sort of thing before, and it seems that if I keep thinking about it, more and more changes will take place. You know, the ol' "Well, what if I did this"? It's part of the fun of building a rifle to suit your wants/needs.
