Here's something I noticed just the other day. I was working up loads for my 338 RUM. The 300gr SMK bullets were flying over the Oehler at about 2,650 ft/sec.
My buddy shows up with a Blaser (sp) in 375 H&H. He was sighting in the rifle with Federal Safari ammo with the 300gr TSX bullet before leaving on his Alaskan moose/bear trip. I shot his rifle & load over my chronograph to see how fast the big 300gr bullet was going. To my surprise, the 375 H&H was only going 2,515 ft/sec. The back of the box only claimed a velocity slightly faster. That's 135 ft/sec slower than I am shooting the same weight bullet from the 338 RUM.
The 338 would have more muzzle energy, flatter trajectory and (presumably) more terminal energy than the 375 H&H. I can't imagine that the 338 mags wouldn't be good grizzly medicine.