Quoted:
Thanks for the info..I guess I agree if it was needed, Glock would have made it to begin with...
I've fired well over 250,000 of my reloads through my Glocks. I do use Wolff steel guide rods (they're not stainless) in some of my Glocks, but primarily because I shoot a lot of different loads and even calibers through my Glocks. As to "if it needed to be different, Glock would have made it so," that's pretty shortsighted thinking. Glocks' engineers don't have the same priorities in designing recoil spring systems as an informed consumer might. Does it really make sense that a 9mm G17 has the same recoil spring as a .357 Sig or .40 Sheitz und Weazel on the same platform? There. Now you have enough info to figure it out. Why do you think the Glock engineers decided to use the same recoil spring in those different calibers??
At any rate, I typically use a factory-strength recoil spring in my 9mm Glocks. I use 20-22# springs in my G20 and G29. I use 19-20# spring in my G21s, unless I'm shooting .40 Super uncompensated, then I might go to 24#.
Wolff Springs' guidelines for determining recoil spring weight make sense to me: If your pistol is ejecting brass farther than about 8', then you could probably use a stronger spring.