The 160 grain Sierra game King works well on big mule deer at range and elk. I have three grown sons and we all live in the Rocky mountains and hunt deer and elk regularly and that combination works well
large calibers misused will contribute to poor shots. If people can't withstand The recoil or the muzzle blast the shot will be off. It's better to pick a caliber you're comfortable with and make a very accurate shot
I have had 3 Mark fives in .257 caliber. Great guns but make sure you decide on the right ammunition and the right load.
If you can work up a hand load yourself or do it with some of the real benchrest guru's that goes a long way. Over-the-counter ammo depending on the bullet is almost a hundred...