I prefer rhe 6.5 to the .243, but only because i like to tinker and ive been bored with the .243 for years.
I does deliver enough extra bullet weight to make a difference tho im fairly sure that 90% of hunters wouldnt notice on game, and the other 7% are probably going for something heavier, and 3% are dedicated to making the 6.5 work.
Personally im kinda wanting another 250AI, but i think i mostly want to shoot 120ish gr bullets.
First of, I love Skeeter as well! Those are two of my favorite books ever. I am lucky to have a few copies of each to pass on to my boys.
As to the .243 vs 6.5...I will keep my .243 and likewise go up to the 06 if I need more punch. Having said that I understand why people like the 6.5 and what it offers however I am not one of them yet. I do have some ideas for a mountain hunting rifle in 6.5 but haven't yet fully worked it all out in my head. My gut is telling me to ditch the 6.5 all together and go with the 280AI.
I am glad we have so many choices now, even if they all do somewhat overlap.
Ive owned multiple 6.5cms, a 6.5-284, 6.5prc and a .280AI.
End of the day theres no replacement for displacement, load any of them to the same pressure and youll get about 200fps less from the CM as the larger 6.5s, and 200fps, and 20gr less bullet mass than the .280AI.
If you want that extra 200fps and 20gr of bullet, your gonna get kicked about half again as hard. The larger 6.5s are about 1/3 more recoil....its enough to be noticeable.
If i were building a true UL mountain rifle, id consider that i can cut two pounds off a 6.5CM, and still have less recoil energy than a 280AI. Id also consider the game likely to be hunted, if I needed/wanted the extra bullet weight (20-40gr or so) then id for sure go 280, 280ai, or 7mag, and just carry a heavier gun, or deal with 30ish ft/lbs of recoil.