Shawn Carlock did the edge on the 300 rum because it first of the Rums ,,, he saw and opportunity too have a kick *** 338 and a standard mag bolt face, the 338 rum didn't come out until after he and many others necked up the 300 too 338, 358 , 375, 416 458..
I load everything the same way .. specially on big cases I've witnessed and shot 1000's of rounds through 338 rums, 338 edge's 338 lapua's 338imp 338 snipetac's 33XC's 338-378 Bee's just too name a few.. 1000's of rounds and they all tell me the same thing .. they will run slow and be accurate but what I and most other individuals have witnessed with big cases is the closer you get too there top end node they really come on and shine, lower Es's tighter and more consistent groups etc.!! same with big 7's big 30's big 375's
and there is not a 200 fps difference in either 3 when loaded correctly and to their most potential using identical components,.. when you have the ability too have all 3 at the same time its pretty easy too have information based on facts. they are ballistic triplets ..