One comparison that is easy to get numbers for is to compare the AM lines, Allen Mags
, if you lay out the 7AM with the 200 Wildcat the 338AX and the 338AM with the 300SMK the ballistics of the 7mm are more appealing to me, less wind drift, less MOA more velocity with less powder and a lighter rifle. I don't think and elk would know the difference between the 200gr bullet vs the 300gr bullet as the 200gr is retaining so much more velocity. But it seems to hinge on being able to shoot the 200gr bullet.
That all being said I would get a 338 that pushes a 300gr bullet a 3000fps + just because of the barrel life and those chamberings have proven to be super stable and reliable performers.
If I were to go the 7mm route
I would build a switch barrel Savage, run the 7WSM with the 180 Berger and shoot it constantly and have a 7RUM barrel that I could run the 200gr bullets out of as a single shot.