I have never seen a ML barrel worn out. And I have handled many a gun that was over a hundred + years old. Now I have seen a lot of dirty, abused, and corroded barrels from lack of care. I have also seen a lot of leaded barrels that look like the have been shot out, but needed nothing more then a good lead cleaning! But I would have to agree with MD about the crown damage do to ramrods. And Bronko's idea of blast erosion, but that would entail a small area of a barrel and not the entire length.

JMHO guys.