Another test that is non-destructive and almost invisible is to perform a hardness testing - this leads to the ultimate tensile strength of the metal.
With a modern chunk of steel you can take repeated measurements all within the same small area of the surface and get pretty much a consistent reading +/- reading errors. The measurement you like the most is the one you keep. Now, with Damascus, I've noticed that the readings are not nearly as consistent at all, they seem to center around two values, one high and one low. This makes total sense since we have the sandwich of the weldable soft iron layer and the hard solid stuff.
Is it foolproof positive? I don't know - it would depend on the fineness of the whole works to make for an inconclusive result.
Would it matter? no, not much since you'd at least get a good handle on the actual measured strength of your gun.
