So was it ever decided what the mystery mark is?
I have at least three guns with the mark, along with bore diameter and either a 74 or 75.
I am curious not so much as to the origin of the markings but why the guns are so marked. Could it be that the barrels have been back bored? On one of mine the original .729 bore diameter has been crossed out.
Edit: can't get the images to work. Maybe someone can help?
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