I have read that the Adams and Bennett barrels come from a variety of sources, which means the quality can vary. I have heard Green Mountain, Wilson, E.R. Shaw have been sources at times.
I personally know of two which were purchased from Midway. Neither was exceptional, about equivalent to a standard Win. or Rem. factory barrel (a .243 Win. and a .257 Roberts) The Roberts barrel required firelapping to get out a tight spot before it would shoot better than 3" groups at 100 yards. After firelapping it would group around an 1".