I'm still pretty torn between 308 and 6.5. 6.5 seems to be the more accurate round but when comparing ammo prices the 308 is the better choice. I can find federal smk 168 grain for 18$ a box which seems like a hell of a deal when compared to around 24$ a box of the cheapest 6.5cm i could find. 140g hornady american gunner. The federal berger boxes are around 29$ a box.
600-700 yards is about the farthest distance I have been able to find anywhere near me where I could shoot. I don't know if investing in a 6.5 and taking the hit on accurate target ammunition would be worth it if I can never really stretch it out.
Pretty sure that within 600-700 yards, the 308 and 6.5 are darn near identical and you'd be splitting hairs to say one is better than the other. Pick which caliber you like, can afford to shoot more and go. If you're primarily hunting, I do believe the 308 would be a better choice due to bullet choice (For both hand loading AND factory). And the extra few hundred FPE the 308 has certainly won't hurt you. But if you want a 6.5, go for it, it'll probably be my next Whitetail gun.
Also I wouldn't say that the 6.5 is a more accurate round, it all depends on the gun. You could maybe say that the 6.5 is more likely to be built in an accurate gun/match rifles etc.