This is Very True !
I built two 338's identical, 30" barrels , carbon , t-3 Termanator, Remington actions . The 338 Rum and 300 gr bergers hit 2883 ft.per.sec and the 338 Edge 300 hr bergers hit 2884 ft.per.sec.
The Rum , Edge are so close ....it depends on throat work and if you add the +P...