If they are related then there must be a comparable number. We know that barrel steel must withstand pressure exceeding 62,000 to 65,000 PSI. We don't come anywhere near that with BP.
In particular; "not certifiable for any gun barrel application, black powder or smokeless." Who or what determines cert specs for black powder? It would seem that if there were any no barrel maker would dare to fail following them. Further, those specifications would probably be commonly known in the ML community and barrel makers would proudly assert the use of "certified" steel.
As to the documentation of the burst that you described I'm not overwhelmed. It fails to account for human nature and the tendency to deflect responsibility even when there are no consequences. After years of taking auto accident reports from all parties involved in the event I can tell you that it's extraordinarily rare to have multiple parties agree on the most pertinent facts. It's internalized cognitive dissonance at work. These are mostly honest people protecting their own self image and beliefs about themselves.
Here's a suggestion for you. And not offered in anything other than good faith; why don't you acquire a 12L14 barrel and do some serious experiments such as repeated discharges of short started balls or repeated discharges of serious overloads. It would be interesting to see the results.
. I'd do it myself but on my fixed income it's unaffordable to waste a barrel.
