perhaps it would be useful to note that 'case coloring' and 'case hardening' are sometimes interchangeable terms. Many 'case colored' guns today seem to be just that - colored. Makers use various chemicals (like cyanide) to obtain a certain color. Early Perazzi guns come to mind.
Case hardening in traditional use was to apply a tough outer skin to metal using heat and carbon, quenched to set the hardness, which resulted in the distinctive coloration.
May be my imagination, but case COLORING does not seem to be as durable as case HARDENING colors. Perhaps soem of the smiths and rocket scientists could enlighten me on this.
