Is it necessary to blue or otherwise finish the inside of a tube type receiver? Some of these sub gun semi builds are beginning to come together and I was just curious whether it was necessary.
Looking at the cut receiver pieces it looks like they were blued but I wonder if something like guncote would be better to use since they are semi auto or would a cold blue be fine with a guncote finish on the outside. I tend towards the latter when I get to the build. Cold blue the inside and paint the outside. Anybody know?