It was determined a long time ago that "proof" was what was required to make shooting an acceptable risk. The Europeans used the professional Proof House concept and the Americans went with self-certification by each maker. If you send an old gun to a European Proof House, it will get the same treatment as a new gun. If it passes, and most do, it will be almost as safe to shoot as when new. This system has worked for about 150 years now.
The issue with Slivers proposal/request is that the statistics will be so wide as to be meanigless to an individual gun. There will be no usable "average" for damascus construction or condition. There has been no meaningful "average" for damascus use. There will be so few failures that no meaningful projection can be made beyond what we already generally know.
Unless you are dealing on the ragged edge of the steel's strength, "n" is a very large number, large enough that it is not likely to be approached in shots fired in a shotgun barrel. Experience says that if no metal "moves and stays moved" in proof, the gun is vastly unlikely to fail in usual service.
Every time you fire a gun you take a risk of something letting go. Every time you take a breath, you risk inhaling something carcenogenic. The first is optional, the second is pretty much required. Both have a pile of experience that says they are risks worth taking in the greater scheme of life.
