I wouldn't consider it on a M21, but it brings up a good point; case coloring is yet another attribute that fell by the wayside as guns became more 'advanced'. If I were in 1935 buying a big-buck gun, such as a M21, I'd be pretty disappointed in a blued finish. I still would be today. A blued receiver screams "corporate cost cutting measure" to me. Is there any other high-end shotgun that gets shipped with a blued receiver?
Case hardening is only needed when low tensile steel is used. The reason low tensile steel was used on receivers was that the material was easy to work but soft. The surface needed to be hardened which resulted in case colors as a byproduct. The coloring effect became so popular that it continues today on many firearms whether it is needed or not. A blued firearm such as a Model 21 or Superposed signifies the use of a modern material. The decision to not use case colors was not an economic one but a material decision. Now individuals expect case colors whether the firearm actually needs them or not. Those case colors that result from treatments other than actual case hardening may fade as with actual case hardening colors.
That said, i ordered my RBL with case colors because i wanted a darker reciever for the field. If the RBL would have been offered with a blued reciever, I would have been just as happy or happier.
-Dick
