Hi Alx, In reading more of your post, I think the reason for the breakage might be two fold, and some of it my fault... the first time, it broke immediately and may have already been fractured, and other then being numbered, old dark and dirty I have no idea.. the second pin broke right thru the number as well, but I was shooting 9MM NATO ammo and was having all kinds of issues until the firing pin broke and the day was done... It wasn't visibly broken when I started and I had looked at it upon a prior inspection. it was a matching gun too! I just don't trust any / all junky WW1 firing pins anymore...
... best to all, til...lat'r...GT