I'm considering a hunting/ long range target rifle in .308...
Geo-Erudite gives an excellent hint.
The .260 Rem and 6.5 Creedmoor shoot flatter and display less wind drift than does the .308 Win. They also outshine the .270 in the hunting field even though the cartridge is based on the .308 Win.
The 6.5 caliber also has bullets that are good to go for just about all North American game.