Ringing is but one step in evauating the soundness of a set of barrels, and not conclusive by itself. A close look at the solder joints and pressing on the ribs will reveal problems, lifting, or looseness. Look for rust or corrosion or bloom from the salts or chemicals that may have been used in past rebluing. Tip the barrels from end to end and listen for loose crap, corrosion, or solder rattling around between the tubes. Some recommend immersing barrels in hot water and looking for air bubbles escaping. I'd rather not do this unless I could be sure or getting the barrels warm enough, long enough to completely remove any moisture trapped inside. Some guns had a small vent hole drilled in the lower rib and this hole may have been drilled later by someone doing a reblue in order to rinse and drain any trapped salts. Hot bluing is certainly not recommended on soft soldered doubles, but many have been done and they got away with it. But trapped salts may be quietly eating away between the tubes. If everything else looks good, but they don't ring like chimes, I'd be inclined to shoot away and inspect overall condition after shooting and cleaning. I haven't heard of any catastrophic failures due to loose ribs, but that could be because they guy it happened to is now blind or fingerless and can't reply. Please "chime" in on this if I'm wrong as I'd hate to see anyone get hurt or damage a nice gun.
