I believe that during a period in the 60s and 70s, Winchester used re-cast metals in their receivers. The rifles are just as strong as any other Winchester but the bluing either fades or turns plum color with age. I do not believe a re-blue will help that much as I understand the re-cast metals don't hold the blue as well. There are finishes available to protect the metal and up in the Custom Rifle Forum there is a thread about 'finishes' that may be of some help to you. Mikey.
