300 WSSM, they make one? I am not as up on the newer rounds like I used to be and I tried to goggle it and could only find the 300 WSM.
Looking at the other rounds in the WSSM series though I would imagine that it would be pretty comparable to a really expensive to shoot 30-06 performance wise. If that is the case I would stick to the good ol 30-06 or better yet the .308 Winchester. The WSSM rounds are a nice concept of effciency and can often accomplish the same performance level of standard calibers using a little less powder. However their availability and thier cost give very little in the way of an advantage. There also doesnt seem to be a lot of guns chambered for them as well making them a bit of a rarity in the gun world.