if you have a drill press - or can firmly mount a drill - get the part straight in the chuck and remove material with a fine file, the polish with paper - not too much pressure on a small part - you may cant it in the chuck. go very slowly and measure often.

you may need to anneal it and then retemper -

Rick, Excellent idea. Thank you!

Bruce:
In an effort to preserve a fine English gun, I've sent you a PM. Hopefully, it will be well received.

Resolution!
 

A gracious fellow member has offered to rebuild my broken firing pin. My thanks to everyone's contributions. This forum restores my faith in humanity. Good people come here. :cheers: