I think that 6.5 creedmoor would be a good deer drive gun. Have no experience with the 338 feed. I know people that have used the 358 win for deer and their neither was a problem with to much gun. A good friend has a dpms in 308 and really likes it used it last year deer hunting. Me personal would like a ar 10 in 7mm/08. Sounds like you are set on the 338 Fed. Me personally I would like two.complete guns then one lower and two uppers.