I inherited a Ruger .22cal New Model Single Six revolver. Serial number indicates it was produced 1981. It is a steel blued frame with a stainless steel cyclinder. The cyclinder is marked ".22 WIN. MAGNUM CAL." I tried to research this model but I can't find any reference to a blue frame with stainless steel cyclinder. Does anyone know if this a factory produced pistol or did someone fit this steel blue pistol with cyclinder for a different gun? Also, Ruger manual states that only .22 WMR cartridges can be used as the cylinder is not fluted and will not fire any other .22 cartridge safety. Any thoughts on this issue? Thanks for your help.