Re: The best long range caliber
For deer 500yds and in, the 6.5-284 or the 6.5-06 are superb. You can also use the 270 but that's pretty boring (I am about to become boring). If you want a bit heavier bullets, then the 280 and improved versions are fun.
For new fad, the 7WSM, 270WSM get my nod. If you believe speed above all, 25STW and similar are fun.
I am not a fan of the 30cal unless you can launch 210 and heavier bullets. That would make that rifle heavier then necessary or need a muzzle brake. Also, way more gun then needed for the intended ranges and game.