[Dfariswheel]

The stainless steels that are used in firearms can be heat treated, but you have to know WHAT the steel is, and what procedures are needed to bring it to what level of hardness, and for what purpose.

For the most part, a gun with stainless steel parts has already been heat treated to the ideal level by the manufacturer.
Attempting to heat treat it to another standard will likely cause serious problems.
Gun parts are treated to a certain level for the purpose the part is to be used for.
Making it harder or softer will usually cause broken parts, or unsafe parts.

In other words, a gun maker doesn't "save money" by not hardening a part to a higher level. The part is hardened to the ideal level.....no harder...no softer, as determined by well educated firearms engineers who fully understand the stresses involved.

Bottom line, you're not going to outguess engineers and metallurgists with masters degrees.