I have recently gotten a new breech block manufactured for my 9cm C/73.It is based on an original and has turned out extremely well.There is still restoration work to go but progress is being made.This is the Link:
As usual, your restoration efforts follow that personal persuit of yours for perfection & faithful to the original. This is perhaps one of the least appreciated field piece used in the Great War. As you state in your attachment, many were pressed into service in the AA role. Used predominantly in static air defense, they were adapted to several different traversing mountings; some of which were field expedients. More than 600 were utilized in this role.
Ralph, the reproduced breach appears excellent; Please keep us abreast of your progress !