.270 WSM
Think .270 + a couple hundred fps. in a short action.
My 7mm WSM [only 0.007" difference] shoots 150 gr bullets @ 3100 to 3150 fps chronied.
Ballistically speaking... take what you know about the 7 Rem Mag, and that's what the .270 WSM will do [more or less]. The difference is that the 270 WSM offers less selection in bullet weight, fits in a short action, and the ammo costs a bit more.
Or, take what you know about the .270 WCF... Make the bullets go a couple hundred fps faster, increase the recoil a bit, take at least 1 shell out of the magazine [they're fat, so usually only 3 in the mag] put it in a short action, and make the shells cost more than double.
That is the .270 WSM