Not having read all posts, I will put my own spin on it.
My interest in LR shooting began simultaneously with a 264WM & 300WM with informal rock busting and steel. I moved on to F-Class with both the above cartridges, then built another switch barrel that has so far had 22-250AI, 260AI & currently 6.5x47.
You really don't need a 30 cal if you already have a 7mm.
As we are limited to .323" bullets here in F-Class, a few of us tried getting .338" cal accepted, to no avail, after we built 338 Edge's and realised their potential.
We use these informally on practice days, and I also built a 338-416Improved 40degree and it shoots flat! I'm still waiting on a McMillan stock for it, and the brake to be finished.
We're not allowed to use brakes on our ranges, so the rifle weighs 18lbs all up and loaded.
As you can see, I have a preference for .338" cal...for a very good reason, it bucks wind, hits WAY harder and is scary accurate IF you can handle the recoil WITHOUT a brake.
It's also perfect for deer or elk, which is why I also have a 338-06 and 338WM in a few different hunting rifles.
Cheers.