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Radley Balko has a great overview on the fundamental flaws with ballistics forensics[1]. The tl;dr is that the core claim of ballistics forensic analysis, that it is possible to reliably differentiate between two models of the same gun using just casings and shells fired from those guns, has never been proven to be valid.

[1]: https://radleybalko.substack.com/p/devil-in-the-grooves-the-...

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Great read, had no idea it was so incredibly bad! Definitely like pseudo-science, with extremely poor reproducibility. And a lot of dishonest massaging of words to make it seem much more certain than it is, benefiting the prosecution only. Imagine being innocent and having an “expert” take the stand and say it’s a “practical impossibility” that the bullet was fired from any other gun. The analogy with the tarot cards seems appropriate.

Seems like markings can be exculpatory at best, for instance that casings or bullets clearly don’t match, but that the “unique markings” of an individual barrel is complete BS, especially with precision mass production of modern firearms. But in practice, it seems to rarely exonerate suspects, even if the evidence exists.

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