@ S Bruce. That's one awesome Muley!!
As many of us have noted, there is no substitute for proper shot placement.I personally love a 25-06. It's not my elk gun but I have taken 2 elk with it at 60 and 468 yards, both with one shot each. I did it because I know I can. My 25-06 is super accurate, I practice with it to 600 yards and am confident it will do it's job if I do mine. And there lies the rob, the gun irregardless of caliber is only as good as its operator.
What ever you pick, practice, practice, practice, and don't take a shot you haven't practiced.