Jim, I'm an Iowa hunter safety instructor. One of the "training aids" we have is what's left of a fluid steel double after a burst. I don't know what caused the burst. Miller's certainly right that most are the result of an obstruction, and that might well be the case on our "training aid". But it's certainly a blown steel barrel. And I recall a Remington recall of barrels (1100's I think, but I could be wrong) after some failures. Also, I believe there have been either Krieghoff or Perazzi barrel failures reported. The latter on target guns, which should be less likely to fail because they're built to withstand a lot more shooting.

So even modern steel barrels fail. Greater failure rate in Damascus barrels? Statistically, that would be hard to compare. And you're also comparing 100 year old barrels to new stuff.