I'm aware that you remove wall thickness when you hone a barrel...you also increase bore sixe.

But...If you have plenty of wall thickness to start with I'd rather have a barrel that's been honed and still measure up.

The problem with alot of these older shotguns is that they might have already saw several honings in their life...bore diameter tells the tale.

Rust is something that really can't be stopped without it's total removal...kinda like a cavity in a tooth.