I had this problem happen to mine some years ago. I did not replace the firing pin or spring (I'm cheap). Instead, I removed both, and spent a lot of time polishing the inside of the hole in the frame with either a very, very fine grit sand paper or steel wool (Can't remember which, it's been so long ago), as I could find no problem with the pin. Although, I probably also polished the pin too.
Good luck, and let us know how it turns out.