Cute.
Robert, I went over the thread and found an important post I had missed. Your point concerning the gun being bored out for ballistic advantage is germaine and probably explains all. The 770 wadding was new to me,thanks for that.
So, the proof marks become irrelevant because the gun is made to produce income not value.
The problem here is without provenance it will take a price hit when you go to sell it.
So here's a case where proof means nothing to the man who bored it out for special use but sorta screws those that came after him
