From my own experience and contact with RimfireCentral, it seems the Ruger factory target barrel groups better than  the stock barrel, but not quite with say, a Kidd,  Volquartsen or Fedderson.
   If you can find a very early 10/22, it should shoot good also.  My first 10/22 was a first year model,  #66XX, it would outshoot some very expensive rifles.  I have been told that the earliest 10/22s had barrels supplied by an aftermarket maker..
  Who knows?   Green mountain isn't too far from Southport, CN !  

  Only kidding, Green Mountain, in Conway, NH ..wasn't started until 1976