Drew,
The worst of the pitting is in front of the chamber. i haven't measured the distance from the breech, but definitely within 9". I wish the damage were further down the barrel, but it is what it is.

Is Briley my best option for custom inserts? It would be nice if I could find something less than full length, but longer than the forcing cones, in order to reduce the added weight, but I don't know if that is feasible.