My first thought when I saw the title of the post was 6.5-06 AI, but not an option, so went with the 6.5 PRC for the velocity/power farther out. The 6.5-284 Norma appeals to me, too, as it almost seems to have a 'cult following.' Must be something special about it. The sentimental part of me wanted to pick the .264 Win Mag just because I like the classics. I also appreciate the .260 Rem as I'm a fan of anything based off the .308 Win case. So many great choices.
If it was only out to 700 yds I’d pick the 6.5x47. Mine holds just over 1000 ft-lbs at 700 yds with a 130 Berger hunting. Seems the 6.5X47 doesn’t have a very large following for hunters. I personally have two of them.