What is meant by the term ‘hardening’ on a shotgun?

SHOTGUN STEEL HARDENING
Mike George
A very thick book could be written on hardening techniques for different steels, and there is no easy check you can perform at home to find out if the parts on your gun have been hardened correctly.

However, the hardening techniques used by Miroku are usually spot-on, so I wouldn?t worry.

Steels are usually hardened by heating the components, then cooling them rapidly by quenching in oil or water.

Hardness can also be increased by cold forging: this is known as ?work hardening?.

There are many different grades of steel, but all are alloys of iron and other elements.

All grades have different qualities, so there is no one hardening technique that suits all of them.

Machine components which have not been hardened properly wear out quickly, and that applies to gun parts, too.