Firing pins for Lefever hammerless guns were once available at Gun Parts Corp. (formerly Numrich). I don't know if the size or style was different in the sidecockers. The firing pins in the later hammerless guns that I have seen were something that any machinist could easily reproduce on a lathe with oil hardening drill rod, and then harden and temper. No problem if you can get the correct dimensions. Guys like Keith Kearcher or Buck Hamlin who repair and restore Lefevers on a daily basis could probably do this in their sleep. Putting off the job can lead to what happened with a DS Lefever that I am working on. The gun was disassembled for a broken hammer spring. The gunsmith became sick and died. His son sold off the contents of his shop and the parts for this gun were scattered to the four winds. I bought the receiver and forend at one gun show, and the matching serial no. buttstock at another gunshow. Somewhere out there are the barrels. What are my chances of reuniting all of the pieces and parts after 15 years? I'd hate to see your sidecocker suffer the same fate. Good luck.