I'm checking over a Damascus barrel set for a friend. There is considerable erosion just ahead of the forcing cone in the right barrel. The pics tell the story:





Lengthening the forcing cone could take care of this. The chamber is already 3" deep and not knowing the actual depth of the damage concerns me. Is it really worthy of consideration? Where does one draw the line?

Yes, I did write a book. It's called "The Classic English Double Barrel"