Wilson Arms makes a pot load of AR barrels and have been making them for a long time. I believe that RR used some of the barrels also that White Oak Armament uses their blanks, should be a decent enought barrel.
I think Furtaker_.223 makes a good point, are you looking for a short or long barrel, (16 or 24) and what do you expect out of your barrel, White Oak cuts a pretty decent chamber on their barrels.