The sage of modern day case hardening, Oscar Gaddy, wrote a series of two articles long ago that were published in the DGJ. I have them both and have read them many times. One of the things I remember most vividly is the electron microscope pictures of the surface of a color case-hardened surface.
That picture shows physical irregularities that are in the shape of tiny prisms which refract light in ways that cause the human eyes to see various colors.
I can completely understand how physical wear can affect those tiny prisms and cause them to not refract light the way they did when new, thusly affecting the colors we see. But, I have yet to be able to understand how sunlight could reshape those tiny prisms. We are told regularly that direct sunlight can do this, and that we should keep color case-hardened guns out of direct sunlight as much as possible. I even practice this myself, just to be safe.
My question is this ........ what PROOF exists that sunlight can do this? And, if proof actually exists, has it ever been explained how that happens?
