I am guessing from the photos (though I have read of this action before but never saw it) that the cammed front surface of the hammer will push the bar forward on half cocking, and the bar will lever the firing pin backwards and out of contact with the primers on closing the gun.
I speculate that all this was in order to avoid using coil springs around the firing pins. Coil springs were a no no. A coil sprung firing pin would have accomplished the same backward movement as the complicated toggle.
Makes me appreciate the Stanton automatic rebounding lock even more.
