I haven't read the whole thread, just most of the dry-firing stuff on the first page.
I can speak with some authority on dry-firing, and so I will.
Through dry-firing, I've broken the firing pins on a Smith K (M19 4"), a Colt Python, and a WWII P.39 (not just once, but TWICE!). As a result of these "leaning experiences," I will not dry-fire ANY centerfire handgun without a snap-cap in it, EXCEPT a 1911. I've been dry-firing 1911s for over 50 years and the only damage I've ever seen was on the cheap cast firing pin of an ODI viking--the dry-firing was peening the struck area to where it soon wouldn't have gone through the firing pin stop anymore. I filed the peening back and then replaced the junk firing pin with a common USGI unit and had no further problems.
I make my own snap-caps in .38/.357, 9mm, etc., by filling the primer pocket of a fired case with GE silicone caulk. I've heard that a common pencil eraser will work, too, and should, though I admit I've never tried it. The whole idea is to keep the unsupported TIP of the firing pin from coming to a sudden stop. Think of those desk toys with the five suspended ball bearings--lift the ball on one end and let it go, and what happens to the ball on the other end? It goes flying! The same principle is at work with your firing pin and the same thing will happen to it if you dry-fire it enough.
Here endeth the lesson.