I would not hunt with the ELDX bullet from a 6.5 Creedmoor. While it does kill them dead, there is a good chance you will have no blood trail. Some people don't care about that. Since I've only ever taken double lung shots, I just feel better knowing there will probably be a good blood trail. Otherwise, they work well.They actually religiously hunted with and recommended the 6.5 Creedmoor. They put the round 2 in above the front shoulder. They were adamant about the 147 grain ELDX projectile. They said the bullet expanded and didn't over penetrate and dumped every bit of the energy into the vitals.
6.5 Creedmoor isn't much different from the 6.5x55 and that's tried and true.
6mm Creedmoor isn't much different from the .243 and that's tried and true.
So I think they're both going to do a good job.