The only barrel i will only use on a 6.8 is a ARP barrel, priced right and are unbelievably accurate! I only use PRI mags, as the others i had nothing but problems! I have a suppressed 12.5" short barrelled rifle that i cannot put down! Its my go to rifle from hogs, whitetail and exotics. Fixing to build another, was going to go to 20" but after doing a little reading decided to just do a 16", as it seems 4 more inches gives you not enough velocity to worry about, but then again i shoot evything suppressed and im not worried about the little extra blast from a shorter barrel. For all your 6.8 needs!
http://68forums.com/forums/forum.php. 
