I have both the 06 and 270.
Get the 06 to satisfy your itch. I would have no problem shooting elk past 300 yards with it or even my 270. As others said, practice and shot placement are more important than the magnum stamp on your case.
No need for the 300wm in that range. Or spend the money on good gear.

All of them do something better than the 30-06, but none of them do everything as well.