when should a cold blue finish be applied on a rifle
Bluing (steel) There are also methods of cold bluing, which do not require heat. Commercial products are widely sold in small bottles for cold bluing firearms, and these products are primarily used by individual gun owners for implementing small touch-ups to a gun's finish, to prevent a small scratch from becoming a major source of rust on a gun over time. At least one of the cold bluing solutions contains selenium dioxide, to accomplish the bluing. Cold bluing is not particularly resistant to holster wear, nor does it provide a large degree of rust resistance. It does, however, often provide an adequate cosmetic touch-up of a gun's finish when applied and additionally oiled on a regular basis, however, rust bluing small areas will often match and blend better and wear better than any cold bluing process.