Comment on Perfect crime

• python@lemmy.world ⁨1⁩ ⁨week⁩ ago

  Just tie a string to the bullet and pull it back out after shooting someone with it, duh

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• HugeNerd@lemmy.ca ⁨1⁩ ⁨week⁩ ago

  Gun barrels are mass produced and are all the same… That “science” is a lot like lie detectors, mostly bunk.

  nist.gov/…/how-good-match-it-putting-statistics-f…

  “But bullets and cartridge cases that are fired from different guns might have similar markings, especially if the guns were consecutively manufactured. This raises the possibility of a false positive match, which can have serious consequences for the accused.”

  That’s double speak for “we manufacture the evidence to fit.”

  Do they ever fire from a control group? Show me the “striations” on a dozen guns of the same age and use.

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  • CelloMike@lemmy.world ⁨1⁩ ⁨week⁩ ago

    I wonder if it’s something that used to work when guns were less consistently mass-produced

    Or maybe it’s always been nonsense, never knew that though thanks

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  • exasperation@lemmy.dbzer0.com ⁨1⁩ ⁨week⁩ ago

    I feel like the article you linked doesn’t support your conclusion, at least for the technique described in the article as an improvement over what people were doing before 2013. Those NIST researchers seemed to conclude that their 3D scan techniques can reduce the false positive rate to very low numbers, even when comparing 9mm rounds fired from consecutively manufactured handguns of the same model. At least if they recover an undamaged bullet that didn’t get mangled by the actual shooting.

    But yeah, the previous method sounds about as reliable as the My Cousin Vinny expert testimony: maybe getting things down to a range of possible models, but not specifically identifying a specific gun.

    Now I kinda wish I had a mythbusters budget for comparing bullet and casing markings to both replicate the NIST study and to just compare whether different manufacturers have very different markings for the same caliber.

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