I will start with saying I have not owned a 300 WSM
. I have the brass, bullets, powder, dies and a barrel in the mail to put one together. That said, I have some extensive experience with the 300 RUM and the 308. Seems like the 300 WSM is somewhere between the 2 even if it is closer to one than the other.
Notes on the 308. I enjoy the round due to its long barrel life. This encourages practice, experiments and overall use. When you use a rifle, you learn to be profficient.
Notes on the 300 RUM. I am afraid to shoot them much because of the limited life of the barrel. Can I get to know them enough to get the job done? Yes. However, when a snap shot has to be taken with minimal time to "set up" on the shot, I am not nearly as likely to succeed as I am not profficient with them. What the cartrigidge is good for is massive amounts of downrange engergy.
My thoughts on the 300 WSM.
Adequete downrange energy for north american big game. Good barrel life MUCH longer than the 300 RUM. Short action for ridgidity, compactness and less weight. A much more efficient case design than the big magnums. Yes there will be less velocity but the velocity loss is minimal in my opinion for the reduced recoil and added barrel life.
All in all I think based on what I have seen and heard is that the 300 WSM is a fine LR hunting round. I will know soon enough.