Re: .300 WSM
Accuracy is the final product of many individual items, the rifle being only one piece of the puzzle. Speculating on accuracy without having some additional pieces of the puzzle is fairly difficult. That being said, most rifles will outperform the shooter once everything has been selected. So, whatever your average groups have been with other quality rifles would be the best indicator for this new rifle also.
MOA or better is easily obtained by most factory rifles (there are some real dogs every now and again).
Can't speculate on energy. We need bullet weight, BC, velocity and environmentals (altitude and temperature).