Re: Which bullet would you go with?
If I were hunting sheep or deer or punching paper, I would use the lighter bullet with the same BC as the heavy one for faster shooting. I would use the heavy bullet for game that required more lead such as moose or bears even elk.
There are 155's out there that have better BC's than several 180's such as the 155 SCENAR which I have personaly tested at .499-.502 at 1K. I have also tested the 155 AMAX at .474 to 1k. A slower twist and longer bbl and I am sure one could get .485-.490 out of that 155 AMAX. I dont remember what the BC is on the 180 SMK, what I do know is that they dont make 1K fired out of a 308 winnie. The 155 Palma, Scenar and Amax all fly straight at 1K from the 308. Some of that is a function of velocity and some is BC.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.