Hmmm . . .No, Jon, that is a common misconception. The recoil spring on a 1911 is ONLY for returning the slide to battery, not absorbing slide inertia.. the hammer spring is what's supposed to control the slide. What you need for hotter loads is a firing pin stop with a smaller radius on the bottom. The smaller radius puts the slide recoil force closer to the pivot point of the hammer, making for less mechanical advantage ( and makes the slide more difficult to rack, too, which is why many 1911s have too much radius).
I printed Bill's writeup and happened to reread it a few weeks ago.A heavier slide spring will reduce the ejection energy (case head not hitting the ejector as hard) but causes other problems like slamming the slide home with too much force. The system needs to be in balance.
Bill explained a lot about extractor tuning for both feeding and ejection consistency and pattern that I didn't know before, kind of a practical explanation which isn't covered so well in books (at least not in a way I understood fully).