Discuss the process of case hardening a firearm and modern chemical methods of case hardening.

Admittedly at the start of this I had no idea how this was achieved but I had seen it a number of times while working for a few different live fire facilities. This is the process of adding carbon to low carbon steel creating a hard outer shell while leaving the inside tough but malleable. Doing this adds durability to the firearm but not so much as to make the entire steel component brittle and vulnerable to breaking. Animal bones were used back in the day to achieve this but today most use Bone Charcoal as their carbon element. When heated correctly the bone element converts to a carbon rich gas that bonds to the low carbon steel surface creating a denser carbon steel shell. The longer it is held at temperature the deeper the carbon will penetrate the low carbon steel you started with. Once your done heating it to the desired level of density the items are taken out of the furnace and quenched with water and oil to rapidly cool the items and get that iconic multi color look to the steel. Please don’t forget to clean and oil the items after you are done and they have cooled off because if not you may come back to find those beautiful items covered in rust. This is something probably best learned with time and lots of practice but if you know someone who can get the result I found with this quick google search it may be beneficial to pick their brain a little.