I'd say the300 win. mag. I haven't had a 300wsm and dont have any plans to(not that it isnt a good round). I do have the win. mag and its a great caliber. If the the wsm is on par w/ the WM factory loads(lots of people testify it is), then its a good performer also. there are two factors that favor the WM and one that favors the WSM. the WM is one of THE most common rounds and shells can be found everywhere plus numerous different loads from the factory. Second it has loads of reloaders potential which by all accounts the WSM does not have. The factor favoring the WSM is the short action. so depending on what you preferr/value, make your choice. I personally dont see any tangible advantage to a short action.