Just a point about making springs stronger. That is done by opening them up a bit. To keep from breaking the spring, it needs be annealed first, as noted above, then hardened & tempered.
The strength, or stiffness, of a spring has nothing to do with the hardness itself. It has all to do with geometry, i.e., the thickness of the metal and how open is the "V" to begin with.
A soft spring will take a set & not be worth a @!*%, but it will still be "springy" over a small amount of travel.
One hardens & tempers a steel spring so it can bend a lot without taking a set.
Sometimes that is a surprise to people, that hardness does not relate to stiffness. As a rosy cheeked college kid it was an interesting experience, tyring to convince the grey haired guys at B&D of this.
I do think it is a neat idea for a Southern gun. Here's the Confederate alteration I mentioned earlier.