If you would like to see if a replacement front toggle is available (the first part in the toggle train is the breechblock) I can highly recommend this person. He is likely to have the part you need and can also do the repair. If you do a search on this forum, you'll find many compliments WRT his work. He has done work for me and it was first rate. He's also pleasant to work with.
Gerald Tomek, 316 W. Straford Dr., Chandler, AZ 85225
Email:
gctomeks@msn.com
Phone: 408-234-6565