[Pawel Janusz]

Something rolling under your rib don't mean loose rib, mostly loose ball of solder of broken end of treaded old bead stud. Here is how to check: put your barrels on desk at medium or dark light room, using strong flashlight inspect every inch of rib by pressing it and watching for separation or rib movement, if that look ok, then gently bump barrels with rubber millet and lesson to a sound, is the sound is short and dead means no parts are loose, is its ringing or long then you may have separation somewhere there, but it don't necessarily is a concern. Except if barrels ware refinished in hot blue bath, that means blueish salts are trapped between ribs and barrels and slowly are eating away solder joint. But let's say that is not a case then here is what you do with eyeing rolling part of solder: the concept is to get is glued inside, hole can be drilled in bottom rib right by the forearm lug, or in solder plug at barrel face, the barrels can be skated so the particle move towards the area and glueing fluid can be injected to glue part in, wipe off excess if and showing from under the rib. Let it dry and if success is achieved them the hole in front of barrel can be plugged back with melted solder and made like it never happened.