So check this out. I've been working with Smalley Steel Ring to find a wave spring that will fit the McClicky. This one is 17-7PH stainless so before you get too excited, stainless is a miserable conductor of electricity. In my ideal world they'll custom make springs out of beryllium copper. The only drawback is the massive cost. It would likely double the price of a McClicky. That said, awesome right?
The main reason I like these springs is they have very large contact area: better for conductivity and less potential to dent the battery. But the real reason is the short current path. In a coil spring the current has to go around and around like the spring was one long piece of wire. With the wave spring each coil touches the next so the path is nearly straight. I'm guesstimating but the difference is 3/8" vs. something like 2 inches. Did I mention they look awesome? I think wave springs should universally replace coil springs in "power" flashlight applications.
Did I mention they look cool? If you want more blabber you can check out my blog post