I've never shot a 300 WM but I own two 300 WSMs.
Took one of them hunting for the first time this last deer season. I ended up shooting two deer with it. I was using a hand load that contained a 165 gr. Hornady bonded bullet traveling right at 3,000 fps. Both the deer I shot dropped in their tracks and never twitched another muscle. To be honest I was very surprised by this because every other deer I've ever taken with cartridges ranging from .223 up to a 30-06 all ran at least a few steps. With the 300 WSM both deer just fell over dead. I'm now sold on it.
