In all honesty you might as well flip a coin on the 7mm or 300.

The WSM, at least in my opinion, have some advantages over the standard magnums.

#1 they don' t have that belt so they headspace on the shoulder which leads to better accuracy.
#2 they fit in a shorter action so the bolt is stiffer and stronger than the longer bolts of the standard actions.
#3 If you are watching the weight of your rifle the lighter weight of the short action is an advantage. Worry about the ounces and the pounds take care of themselves.


The standard magnums will have an advantage in speed if you handload and / or shoot the heavier bullets like the 200 and 220 grainers.