I favor the 165g bullet myself. As a kid I remember the older hunters telling me to use 150grain on deer and 180 grain on elk. I think mainly because that's the choice that was available at the sporting good stores in the 60's.

When I started to reload and looked at BC and retained energy downrange, the 165g seemed the winner. And as a skinny young man in the early 70's the 165g offered slightly less recoil ( or at least I thought so) The biggest Bull elk I've ever shot was with a 165g Nosler Solid Base out of a 30-06. I just never saw the need for the 180. Especially with todays premium bullets.

I now use Barnes 165g TSX in both my 30-06 and 300WSM. I've killed a bunch of elk with the 165g TSX out of the 300WSM. But I think it would make an excellent bullet weight for a 30-06 for both deer and elk, in ethier the Partition or TSX.