I would agree with that, an elk hit with a 338 win acts different than an elk hit with a 300 Weatherby. I've lung elk shot with both at under 100 yards. Both died, 338 acted hit harder. Makes me want to work up a 200 grain hammer load for my 35 Whelan at close to 3000 fps.Sectional density doesn't make up for frontal area.
You can see a physical difference in game when hit by the 33 cal in comparison to a 30 cal.
Same goes going from a 30 magnum to a 33 magnum. They just hit harder and displace more tissue.
Cheers.