I guess “most accurate “ is very subjective which is why you have so many varying opinions here. I can’t add anything to that part but I’ll share my thoughts from working up to 2000 yards.
Personally if my max range was going to be 2200 yards I wouldn’t see any reason to shoot anything bigger than my 300 Norma. To date my 6.5 saum is almost as consistent hitting the plate as my 300 Norma, however its more sensitive in the wind. Both of them I feel like are very capable 2000 yard rifles on steel, and my Norma has more room to stretch it out. My buddy’s 7 saum is awesome at 2000 yards, as is his 338 lapua. I don’t fell like his lapua has that much edge on my 300 Norma at that range, I would argue my Norma is more consistent. We also have the advantage of being at 4200 feet above sea level and DA normally 3500 low end to 6000 high end. In my opinion for us anything over 338 or a .338 variant is overkill at 2000-2200 yards, just like my 300 Norma is overkill at 500-800 yards, I just don’t shoot it inside a half mile.
We are looking to build a 2 mile rifle 375 or 416, as we have access to land we can do it on. That rifle probably won’t see much work inside 1500 just because it will be a waste, we have other rifles to fill that gap. If I could only own one rifle 0-2200 yards I’d have a hard time choosing between 7 saum and 300 Norma they are lower recoil, thus more of a pleasure to shoot. Lower cost and better barrel life, therefore you can put more rounds down range. Rounds down range with a capable rifle/cartridge will beat a bigger rifle with less practice every day in my opinion.
