13 January 2018
I cannot help you with the original question. I have dry fired many match rifles (both rimfire and centerfire) thousands of times without a problem. However, I HAVE broken firing pins while dry firing on the following guns:
1 - Original Ruger Single Six: after the firing pin was broken, it was retained inside the frame (those have a separate firing pin from the hammer) and pounded the chambers before I discovered the problem. It never resulted in a misfire (even with the broken pin).
I cleaned up the chamber burrs, and still have it all these many years later (I DID replace the pin once I learned of it's failure).
2 - Two or three S&W revolvers with hammer mounted firing pins, over the years. I replaced those promptly and started using snap caps.
3 - I traded for a used Ruger Super Blackhawk a couple of years after they hit the market. It had been used hard (probably for quick draw based on observation). It had been dry fired so many times that the aluminum firing pin bushing was worn to the place that it put the firing pin in a bind, and it broke (drawing my attention to the REAL problem). I replaced the bushing and the firing pin (not an easy job as the retaining pin becomes a cosmetic problem). However, it was worth it. That revolver will keep most full charge cast bullet loads on a playing card at 100 yards off a rest. Yes, I still have it, and NO I cannot still shoot iron sights this well due to vision loss.
NOTE: I no longer shoot handguns with out snap caps.
NOTE #2: My father was an avid trap shooter. At the time I am discussing, his favorite shotgun was an Ithaca Grade Four Single Shot trap gun. Those were and still are WONDERFUL guns. Gorgeous wood, beautiful factory engraving, state of the art in workmanship. Further, this particular shotgun was a family heirloom. Dad procured a machined, plated steel, snap cap (twelve gauge, of course) that had a solid, spring loaded, "primer". Unfortunately, unknown to my father, the "primer" was of hardened steel, and despite the spring loading, destroyed the firing pin in just a few snaps. This was a SERIOUS problem. The shotgun was no longer made by Ithaca, and parts were unavailable. Fortunately, Dad was able to have one made from scratch.
Moral of the story, be careful of your snap caps. They COULD be worse than nothing...