I recently broke the firing pin in my ATM backup 45. Its the first firing pin in a pistol Ive ever broken via dry firing. I turned a new one for it and its fine now, but Id just rather not damage them. Hate to have one break when you least expect it or want it too.
So I started looking at snap caps to save the firing pins now that I'm a believer. They were expensive as far as I was concerned, so i made my own. empty 45 brass where I used epoxy in the primer pockets. I first put some silicone inside the brass to keep the wet epoxy from dribbling through the flash hole. Once the set up, I applied the epoxy. when it dried, I filed any overage off and let if fully cure a day or 2. I have probably fired close to 400 times and they are holding up well. It might not last as long as the commercial snap caps, but they can be easily and cheaply refilled, and they appear to work just fine.
I was thinking of casting up some epoxy bullets so I could load the clip and cycle rounds and fire. Not sure how that would work, but its something to do. lol

Why not just use a FMJ and glue it in? I'm using the A-Zoom snap caps. If you can turn a firing pin why not turn a snap cap?

My snap caps are reloaded ammo (no powder or primer) but I fill the primer pocket with hot glue, and when its set, I use a boxcutter to trip off the excess.

They work great.

sounds like some good ideas. Are different firing pin/striker combinations more prone to breakage? I didn't think there was any issues dry firing my Glocks and ARs.

I could turn a snap cap, but why reinvent the wheel. Have plenty of empty brass around and its quick, cheap and easy to make them with epoxy, or as RePete said, hot glue. Bet that would work good too.

As for firing pins being prone to breaking, I always kind of thought that was something carried over from the old days and didnt apply to newer weapons, but I see I was wrong. LIke I said, Ive never had one break before, and I do more dry firing that I probably should sometimes. Just to get a good feel for the trigger pull and such. So even though Ive shot for a long time, breaking firing pins when dry firing is new to me. I did however break on shooting live ammo. It was on my 1863 12 gauge of all things. But that was an easy fix. Then again, so was the ATM. I chucked it up in my mini lathe I use for jewelry, and then mostly turned it down to size using files then finished it up. Im not master machinist, but I can make shapes and get pretty precise with them. I'm pure amateur on the lathe, but I get by.