I'm getting into the late stages of refinishing a JC Higgins 50 (FN Mauser). I just polished, degreased and then blued the sling studs by heating with a torch until dull red and then quenching in oil. The results are nice. In fact it looks so good I would like to do the ejector this way. However I'm wondering if this would be a bad idea given that a Mauser ejector is basically a leaf spring and I worry that heat might wreck it. Does anyone know for sure?

Yeah. Bad idea. I know that for sure.

Just get it warm to the touch not red hot.

Heating a spring to red hot, is not something you want to do. Heating a spring destroys the temper, softens and weakens it. (I cut and fit springs several times a day)

".....With knowledge of the composition and phase diagram, heat treatment can be used to adjust from harder and more brittle to softer and more ductile.

In the cases of copper, steel, silver, and brass, this process is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper, silver[1] and brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further work such as shaping, stamping, or forming......"

https://en.m.wikipedia.org/wiki/Annealing_(metallurgy)

Those aren't blued because working the action will make them ugly fast.

Floorplates look good done that way too.

It is not necessary or desirable to heat parts to red heat for bluing. Clean, freshly polished carbon steel parts will blue nicely at about 600 deg. F in air. This temp will not destroy the temper of a steel spring as it is about the temp used to make it.

RAN

Thanks for the advice. If I blue it I will make sure to air heat it no further than 600F.