I've broken two firing pin noses: One a Model 13, the other a M66. One broke at the range and wasn't related to dry firing. The other--don't know when it broke, but the smithie saw a "problem" with the way the hammer aligned with the slot, and fixed it.
Broke a firing pin on a SIG P239. Don't know when it broke--it still fired with the broken pin. The folks at SIG (back when you could actually talk to a real gunsmith) said to use snap caps. The firing pin can break because if it doesn't hit something it "wants to keep going".
I use A-Zooms. Don't care for the brass kind with the spring. I've found pieces of brass in my trigger mechanisms. Empty shell casing in revolvers work ok for short term. Very short term, they become useless after a few strikes.
A note on dry firing. It teaches you how to pull the trigger properly, and that's good, but it does NOT teach you about anticipating recoil and flinching. It teaches what you should do, but you still have to apply it during live fire. The cure for recoil anticipation and flinching is the very widely known (but not always practiced) principle of concentrating on the front sight until the shot breaks.
Just my thoughts on the matter.