I voted for the 7mm Rem. Mag, that being said all you listed will work fine if you hit where you are aiming. My wife shot and dropped a 280 plus class bull with a .243 Remington in one shot,,,,,,,,,,,at 18 yards,,,,,,,,,from a tree stand,,,,,,,,,broke its spine, it never knew what happened. Now I realize that "NOBODY" would say a .243 win. is a first choice on ELK, but it just goes to show how placement beats diameter.