BCC

What is the date of the Luger? Does it have a fluted firing pin? I have seen this before and I don't think that it hurts the integrity (saftey) of the pistol as long as the small "chip" is the extent of the breach block damage. Depending on how you answer the second question, I would suspect the cause of this damage was a ruptured primer. The force (if I'm right) blew upward and chiped the corner of the bolt overhang. I think, if I understand your description correctly of the damage, that if you check...you will see that the extractor does not put force on this exact area.