I know you are looking for an AR style rifle, but have you given thought to a FAL?
It's not that I'm looking for an AR style specifically (even though I implied that in the title) -- I'm looking for a precision .308 semi-auto that has a scope rail as part of its original design, not an afterthought. Also, one that is rugged and can run reliably clean or dirty.
I have a FAL -- a DSA SA58 Para. I think of that one as a high quality AK in .308 - in terms of reliability and durability, compromising accuracy and ergonomics (i.e. cheek weld with the folder) for longer shots.
My issue with the FAL is mainly that the best optic rail seems to be the DSA rail, and it takes away from the basic ease of cleaning (accessibility) that was designed into FALs. While its a well-engineered solution, to me it still feels like what it is -- a bolt on afterthought.
I am curious if DSA's "Hunter" series is significantly more accurate than their other models, but haven't been able to find a comparison write up. Since I don't have unlimited funds there will be compromises, I understand that, and if their "match" barrels make them comparable to an AR-10, then I could live with the non-integrated rail system.
DPMS seems to be having such success with their LR308s, that I'm hoping that they comes up with a solid GP version, and the street price would be in the $1,600 - $1,800 range.
All wishing aside, given my budget and what's currently on the market the FAL is probably somewhere between my best and only option.