Ballistic investigators can use the scratches on bullets to match them to a gun barrel. No bullet, no ballistic evidence.
Comment on Perfect crime
jaybone@lemmy.zip 1 week ago
I remember some old movie where the murder weapon was a bullet made of ice. First of all, that shit would melt in seconds. You’d have to load it right next to the freezer and then shoot them right there. Was the casing also made of ice? And like what exactly was this trying to hide? Some bullets won’t create an exit wound so what the difference whether they find the bullet or not? Obviously there’s an entry wound.
CelloMike@lemmy.world 1 week ago
python@lemmy.world 1 week ago
Just tie a string to the bullet and pull it back out after shooting someone with it, duh
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.
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
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.
boonhet@sopuli.xyz 1 week ago
Technically you could get much colder ice if needed but it would be serious effort and I’m not sure what the gain is. It would bewilder the investigators if there’s no exit wound AND no bullet I guess.
ShinkanTrain@lemmy.ml 1 week ago
MythBusters did it (twice!). The bullet melts before even leaving the barrel.
They never tried an ice crossbow bolt though. I have a feeling that would work.
grrgyle@slrpnk.net 1 week ago
Hmm we have to try with something else, like a pudding bullet
ShinkanTrain@lemmy.ml 1 week ago
Maybe rethink the gun. They have these things that use rapidly (but, crucially, not instantly) expanding liquid nitrogen to propel sensitive payloads real fast. I saw a study about using them to throw bombs on mountains for avalanche prevention. Maybe a small one could work to ice someone (hah).
Also, there is an ice-adjacent material that could make the bullet named pykrete which is more durable than pure ice (Mythbusters made a boat made out of it one time). That defeats the purpose of an ice bullet somewhat, but who knows, sawdust might just confuse the forensics.
I spent way too long thinking about this.
grrgyle@slrpnk.net 1 week ago
Well I appreciate it.
Would cooling the barrel buy you anything, I wonder?
Chais@sh.itjust.works 1 week ago
An ooblek bullet.
grrgyle@slrpnk.net 1 week ago
Perfect. The faster it goes, the harder it gets. That’s just science.