Colt 901 fits your description of what you're looking for.
I own a POF P-308 16.5" and it's amazingly accurate and stone cold reliable.
Both of the above options use DPMS/KAC pattern 308 mags, ala Magpul. this is a big plus to me for reliability and price.
Only downside to a 16" 308 is the sound level, LOUD!! Perhaps velocity loss also, but I've had my 16.5" out to 600 yards without issue.
Last edited by RyeDaddy; October 3, 2012 at 01:59 PM.