Spring "setting", by the way is dependent on several factors. Wire quality is one, but processing methods can have a significant effect on settling behavior.
And yes, I make springs for a living. None for firearms - at least not yet.
Yep, you can certainly run into some springs that are better than others. That's why it's a good idea to spot check where your brass is landing from time to time. My S&W Commander came with (I think) a 20lb spring, stiff as all get out. Still, brass ejects a 4-6 feet away even after 7 years with that gun and a few thousand rounds.
