Stallones, Then the situation is probably not that serious as long as the rib is undamaged and there is not serious corrosion underneath between the barrels. If you are lucky, the old solder and any contaminants can be cleaned on the loose section, and then fluxed and re-soldered. If it's not possible to do a thorough cleaning job, the entire upper long rib may have to be removed and re-layed. I've done a couple small repairs but have not had to do a complete re-lay job. There are several methods of controlling the heat of the soldering torch to keep from loosening the bottom rib such as submerging the lower portion in water or placing steel rod in the bores to act as a heat sink. Even with a small repair, it would be very tough to clean the joint without damaging the bluing. I might consider J-B Weld on a cheap barn gun, but I ask those who suggest using it on a good double how they would feel about coming home from a shop or gun show with a new baby and finding it had such a repair. It's not irreversible, but it would sure complicate things.
