Good stuff Doc Drew. Was there any comment about the appearance of the grain of the steel. I'd guess that the same steel with a finer grain would be tougher and more resistant to failure. Any comment about possible preexisting defects, maybe the bright metal of the sudden failure is different from the occasional small pockets of dark appearing maybe oxidized pits that may have been there from before the mishap.

Any thoughts as to why the barrel appears as though pressure vented in a limited area and doesn't appear to show 360* signs on the inside of the barrel. I'm only being curious, and thank you for looking at it a whole lot closer than these things tend to be.