I have the WSM's in SP's (270,7mm,300 &325) 130 gr bullet - 180 gr, all perform very well in my 15" guns.
The 325 with a full load of reloader 19 &180 BT will scream along at 2700 fps out of the muzzle.
the 300 with reloader 19 & 165 gr BT will do 2850 fps easy.
the 7mm , reloader 19 & 140 gr BT is at 2870fps
the 270 with the130 gr BT and rel. 15 will do just under 3000 fps
all very accurate as well.