Most DA revolvers will exhibit a drag mark on their cylinders after a bit of use. Over the years, that has become expected/accpectable as it is quite normal.
Up untill the NM Ruger SA revlovers came out, most SA's did not exhibit such drag marks...unless they were previously mishandled or were in need of repair. That being the case way back when the NM Ruger was first introduced, the drag marks on it's cylinder quickly became know as the "Ruger ring".....which will forever distinguish them models as being the first SA revolvers that was built in a manner that purposely allowed drag marks not common to other brands of SA revolvers or to Ruger's earlier models. So in Ruger-speak, the term "Ruger ring" is reserved for drag marks on a NM SA cylinder only. Simular drag marks on a early model Ruger cylinder is simply call a "ring".
That make sense?
DGW