Hi,a customer(I work in a sprting goods store)just bought a Ruger biley Hunter,he wants to put a red dot optic on it,the problem is we can't find one that will fit between the rings,we tried Bushnell,Tasco and Nikon all of which we have in stock,does anyone have an idea what would fit?He wants a 30MM tube,the revolver came with 1" rings but Ruger said they would exchange them for him.thanks for any help.