Hehehehe.. Some consider the .300 mags the ultimate all around chamberings and some consider them neither fish nor fowl...If you want a real NOTICEABLE increase in power over a 30-06, go to a .338...

Just for conversation's sake, regarding using a relatively fast powder in a big belted case... I saw a young fellow set up the bolt on a .300 Weatherby one time...Gas rolled out of the action and he had to hammer the bolt open with a block of wood... He was using a manual published load of 3031, which would be a real fast powder for that case....