What I would love to do you be an AR10 in a 7mm-08 round. That way it would match my deer rifle I already have. But looking online, it seems harder to find the parts. And yes I know the .308 and 7mm-08 are almost the same round.
looking at ammo prices .308 doesn't seem all that expensive. Looking on Wikiarms ammo for the .308 doesn't seem all that expensive.