I have used the 243 to a 375 but for a hunt in rough country I would go bigger. A guide friend says 270 Win. or larger, this for me would also include the 6.5s as well or even a 25-06. The 6mm's will be for hill country hunts usually at a feeder out of a box blind. Any bullet that works for deer will do but I would tend to go for a tougher bullet you could put through both shoulders if needed.
Post up about your hunt please.
