I have shimmed a few guns with metal strips to put them back on face "temporarily". Nothing too loose, but once slightly loose taking up the slack, prevents more looseness. Well as those repairs go, they last a decent amount of time and if the gun is nothing special they might get done again. Why invest time and money in a gun which is likely to be shot just a box or two of shells over a period of years. I have one gun which had that repair which I doubt I have shot once in 20 years. But it is ready if needed. Shim stock and one of the Locktite compounds works well and is completely reversible for a more proper repair if desired. Much nicer than a punch mark or hammering on the joint.
I have done a couple of Flues guns by soft soldering the shim in place and trimming with an exacto knife. It worked well, looked good and served me well for many years until it was sold.
