I have personally honed over 75 Shotgun barrels both Damascus and fluid steel. Some had pits as deep as 11 thousandths which were removed. Will they sometimes be considered out of proof? Sure, but they can still be saved and made usable. I start with 80 grit and end with 1000 grit. Wall thickness gauges are a must. You would be amazed at how many barrels can be honed and still be put back into service safely. But you have to know what you are doing. Most of the shooting value in a Shotgun is in the integrity of the barrels. Epoxy I do not believe is a viable solution.

"As for me and my house we will shoot Damascus!"