How about a SIG 716? I previously owned a Bushmaster LR308 MOE 16" mid length carbine and the fit and finish on the SIG is far better.
In reality, the long action ARs are pretty impractical in the carbine format as you get all the extra weight of the platform coupled with the loss in velocity of a shorter barrel. If you must own the platform in 308 buy a full length precision gun as the 16" version really doesn't have any advantages over the 5.56.
Here is my SIG716 with a pic of the old Bushy below.
Hk USP 45 Expert, USP 40, USP 9, SIG P226, S&W M&P9, Hk 4, Makarov, Desert Eagle 40, Beretta FS92 Centurion, Kimber TLEII 1911A1, Glock 22, SIG P225, 1943 Rem Rand 1911A1, S&W mod 64, Walther PPQ, SIG P229, Browning BDA 45 (SIG P220), Hk45, SIG P230