[Dave King]

Lv2hnt

The key is accuracy not energy. Any of the rifles you mentioned would be fine, the 6mm might be on the bottom end depending on the twist.
He needs to pick the rifle that he can shoot the best groups with. Animal are not impressed by ballistic trajectories and remaining energy, they must be struck by the bullet to make any impression. [img]images/icons/grin.gif[/img] [img]images/icons/grin.gif[/img]

Contrary to the standard hunting crowd, many of us here shoot match bullets for hunting. If you're uncomfortable with that then select from the fine longrange hunting bullets, Lost River Ballistics has the J36, Nosler Ballistic Tips.

500 yards isn't a difficult shot, it's just a shot that seems difficult until you've practiced a while.

For what it's worth, I'd probably pick the 30-06 and buy a few boxes of Federal Gold Medal Match for practice. Once some confidence has been achieved with the rifle and the shooters' ability to hit the kill zone at 500 yards then I'd venture into bullet selection. He'll need to practice at ranges other than the straight 500 to get a 'drop chart' as it may be difficult to get a critter to stand still on the 500 yard line.

If he wants to shoot the 7mm Mag or 300 RUM, that's fine too. Just find a bullet the rifles likes and practice. (Don't practice bad, flinching ruins everything.)