I think the journey to find the point of failure is what many of us here are trying to do.

And "failure" can be somewhat subjective in how the results are interpreted.

Blowing up on the outside, I would consider failure.
Coming apart on the inside after adequate penetration and internal damage, I do not consider a failure.
Poking a hole all the way through with little to no damage to the internal organs, I would consider a failure.

Consideration as to isolated incidents or continuous occurrences must be taken into account.

And thorough documentation must be gathered if either side is to prove their position. Thorough!! A picture of a bullet fragment without visual reference as to what was struck, how far, at what angle, and at what speed, etc.........

Complete data is how you prove a point. Partial data collected is just that..........partial data.

"The difference between screwing around and science is..........writing it down." Or, in other words........complete data.