Here's a relevant thread regarding pinholes. The images and links are gone
https://www.doublegunshop.com/forum...p;Board=1&main=19079&type=thread
Some of the learned comments are very much not; like
"Just under the surface a damascus barrel can look like a piece of swiss cheese."
That has been proven to be wrong with photomicrographs of pattern welded barrels. The high pressure rod rolling and ribband hammer welding (properly done) removes any voids.
There CAN be inclusions; some large.

[Linked Image from photos.smugmug.com]

Here's the link to the 1891 Birmingham Proof House Trial report which Miller referenced
https://docs.google.com/document/d/1cvqRzkg0wEjhAAcFWr8gFi7aPFRsSIJ_hahfDxmrNAU/edit?tab=t.0

Formal metallurgical failure studies, without which, unless there is an obvious obstructional burst, no one can make a diagnosis
https://docs.google.com/document/d/1ZnptAPvQIlWG5n5UU2FmKcFpYtVmOSc4b7K7G9IBs4g/edit?tab=t.0
This includes the study of the Smith barrel which I assume keith is citing. The burst occurred with an obvious over-pressure reload, the failure of the breech braze AND a large inclusion in the barrel wall at the failure initiation.

https://sites.google.com/a/damascusknowledge.com/www/home