I have a .300 WSM in a Browning ShortTrack and like it. Despite what some think, with bullets of 180gr max it is the ballistic equal of the .300 Win Mag.
The 7mm WSM has some advantages as the bullet BCs are generally better. Don
As a postscript, I checked Hodgdon's reloading data. Using 150 gr slugs they show max velocities of, both using a 24" barrel;
.300 WSM - 3410 fps
7MM WSM - 3197 fps
So, with those loads, the 7mm would have less energy for a long way out but would have lighter recoil. However, if the 7MM wasn't enough for the job, the advantage the .300 has wouldn't put it in a different category. Don