Maryland Supreme Court Rules That Experts Can't Actually Tell Whether a Given Bullet Was Fired From a Given Gun

That's the epistemic/factual basis of the ruling, at any rate.

There's always been incredulity about this forensic practice in the back of my mind, but it didn't force itself to the forefront of my consciousness often enough. Because the idea is stupid. Sometimes apparently stupid things turn out not to be stupid...but this idea seems really, really stupid. As the story notes, it's often possible to match calibers and whatnot. But the best that can be done is probably to say that a bullet or a casing and a firearm are consistent--not that a particular bullet was fired by a particular firearm.

   My general, insufficiently-well-thought-out view of such forensic investigation: I'd be willing to bet that it's largely a load of horseshit, on grounds of confirmation bias alone. As I understand it, basically the cops go to a "forensic examiner" and say: We think this bullet was fired from this gun; was it? And that, boys and girls, is how you turn what could have been science into bullshit. To be reliable, this process would have to be blinded. You'd at least have to give the examiner several different guns to choose from. Better yet: several guns and several projectiles (or projectile fragments?). Better yet: you'd throw in a lot of dummy cases in which all firearms and all projectiles were known and none of the latter were fired from any of the former.

   I was on the warpath about this for awhile years ago, but it slipped away in the flood of bullshit we always seem to be facing.

   The Innocence Project is massively stupid in important ways--but they're right about this "tool mark"-matching BS.

   Of course it's possible that this sort of thing is really possible--in fact easy. I'm just kibbitzing here. You might recast these points as: if this stuff really is reliable, that needs to be established...and you should be pretty surprised if it can be.