6.5 PRC is excellent for Mule Deer and Elk even. Using 10+ extra grains of power per round over the CM and better for slinging the heavier pills. Factory ammo can be double the cost of CM. Barrel life is probably half depending. Plinking steel at 1k with a CM is easily doable and will kill all 3 game animals you mention with ease.
28 nosler is whole nother animal. 80 grains of powder per round and is getting up there with the Normas / Lapua based cartridges. More of a barrel burner. But it does move 195gr pills over 3k with ease. So you may only get 800 rounds out of one. Brass and components are much more and factory offerings are expensive and few and far between. Think 4 plus bucks a round.
Still need to know how far your shooting. If you tell me your going to bang steel at a mile mainly then this changes things. Most guys have a bang steel gun and then hunting guns. But 308, and 6.5cm cross over well and have much better barrel life.