I hunt whitetails with a 6.5 creedmoor and 143gr eldx and also a 300 win mag with 200gr eldx ammo. No doubt the Creedmoor works fine but there is no denying the 300 puts them down faster in most cases. Put it though their shoulders with a 300 win mag and the majority of the time there is no tracking involved. Mature bucks in my area weigh up to 200 lbs but not usually over.