David first of all piston rings are an accurately made item, you say that they have not been ground for the ring stops which makes it easier to check them. Lets suppose that you have a Scott barrel of known size IE,long stroke plus .040″=74mm if you put the correct size rings into the bore you would probably have .012″ end gap if you put plus .020 rings into the bore IE 73.5mm you would have about .070″ end gap and if you put plus .060″ rings into the bore IE 74.5mm the ends would overlap each other by about .060″. So although they might look similar the circumference is quite different. Alan Noakes. firstname.lastname@example.org David I have sent you a PM.