So, I just saw another crime movie where they definately connected a gun to a murder. They looked at the Bullets under a microscope. So here is my question:
Wouldn't these kerf marks from the rifling change after a few hundread shots or if the killer just ran steel wool through the barrel and make identification impossible?
They always make it seem to be easy to match bullets tu firearms, but I can't imagine it really being conclusive.
I did not even know this was a thing
>Wouldn't these kerf marks from the rifling change after a few hundread shots or if the killer just ran steel wool through the barrel and make identification impossible?
Yes, the mechanical tool marks are still inside the barrel but not the individual marks your gun had. Just use fast and fragmenting bullets and dont have the same ammo at home/credit card
I think they began realizing in the 2010s, that it wasn't really that accurate, but older TV shows use it quite often to 100% identify a killier.
>Wouldn't these kerf marks from the rifling change after a few hundread shots or if the killer just ran steel wool through the barrel and make identification impossible?
Yes. That's why this is generally disregarded in court, and why the microstamping thing WAS a thing for a few years.
Bullet forensics are pretty basic, despite the best effort of politicians to try to legislate them. The best they can realistically get for police is that the firearm at the scene of the crime would indeed match the caliber of the bullet someone or something was shot with, and that'd be about all they could legally say. Going forward and saying that the rifling matches or whatever would more than likely be considered leading the jury with statements that cannot be proven to be correct, as the rifling would likely match hundreds of thousands of firearms just like the one the perp may or may not have had.
TLDR no, what you've just watched is complete fiction, as is most TV-related crime drama stuff. It's meant to be that way so that you think twice about doing illegal shit because you saw them do X on CSI once and you know they can track you down with Y. Most murders go unsolved. Most criminals aren't caught. They're not gonna catch Tyquone because he left his Glawk Fawty at the scene of the crime and they cross-referenced the serial number to his FFL transfer, they're gonna catch him because right after he murdered someone he went home to do coke and rob a convenience store for a pack of gum.
forensics are only one part of evidence in reality
people only end up on death row because the striations match on TV
the examples you see are just the cases where the planets aligned and a match was made.... the other gazillion times the gun is never recovered or the bullets are too fragmented to analyze, etc, etc.
Its in every crime show.
What do you mean by credit card?
Never buy ammo for a crime with credit card and never do it in the same week/month
I like those, where they take a bullet that fragmented into sub millimeter fragments and use the computer to match it to a given rifle....
they make chemical analysis of lead and use your ammo at home to see if its the same batch. Fucking retarded
nope, they reconstructed the bullet with a computerprogran, doubleretard
BTW I am talking about TV shows
>uses quantum teleporter to remove bullet from home before gun was fired
CHECKMATE CRIMINAL SCUM
thats called democrats
wouldn't that create a paradox?
>Destroying whole universe to stop one murder
Is this real technique or only tv faggotry?
>not using handloads you make in your secret reloading room fired from the most boring S&W revolver you can find being sold by the crustiest senile boomer in history and payed cash for using small bills which you subsequently slice up with a plasma cutter then toss out the window while driving across the midwest
it's like you aren't even trying criminals
Paper patching, 18th century. State of the art.
Isn't there an ongoing federal review of thousands of cases that utilized forensic evidence like this because apparently the accuracy of forensic processes has been grossly overstated for decades?
>Wouldn't these kerf marks from the rifling change after a few hundread shots
Not likely. The barrel is hard steel, the bullets are much softer lead or copper.
> or if the killer just ran steel wool through the barrel and make identification impossible?
Steel wool may be too soft to do the job, but something like sand, lapping compound, grinding dust, etc? Absolutely, that would work.
>They always make it seem to be easy to match bullets tu firearms
Welcome to hollywood.
In reality it's SOMETIMES easy to match bullets to guns, but it's far from certain. There are too many variables involved: did they even recover a bullet? how damaged is the bullet when they found it? Does this given gun even have any distinctive marks to go off of?
It's no different than fingerprints or tire tracks, really: sometimes you get nice clear images with distinguishing characteristics and you can make a good match. Other times you get smeared prints/tracks and you can't match a damn thing.
I think it's more like shoe prints and less like fingerprints. I.e. they can look at the groove spacing, pitch, ect and determine one ( or several ) guns it might have come from.
If they have a suspect weapon they can do a side by side and determine of the evidence round is consistant with the suspect gun but not that it was 100 percent fired from that gun.
I can think of a few cases that "ballistic fingerprinting" really solved but usually it's just an extra piece after the fact. There had been a few where analysis of the bullet determined it to he a not super common gun and it allowed for a focused search that found a killer.
Finding out a bullet came from a glock .40 or a Taurus. 38 wouldn't be super helpful unless you already had a suspect.
>is the fed trying to correct their mistakes
No
That's pretty accurate, but you're missing that sometimes they can tell a specific gun, just like they can sometimes match tires to a specific vehicle.
Examples:
>these tire tracks are consistent with a Honda Accord
>this rifling pattern and twist is consistent with a Glock
Those kinds of matches only give you very basic information, they only show consistency with a very common vehicle or firearm, and nothing specific. But, sometimes you get more than that:
>These tire tracks show a distinctive cut in the tread on the left rear tire; the suspect's truck has the exact same tires and track spacing, and also has that same distinctive cut on the left rear tire.
>This bullet is consistent with a Beretta M9, plus there is an odd scratch between two of the rifling grooves; we recovered a Beretta M9 from the crime scene, and it also has the same unusual scratch between the rifling grooves.
The main point of 'ballistic fingerprinting' and toolmark analysis is to hope you get enough information to use the latter examples, because the former is pretty much useless.
Do polygonal barrels like in a Glock even leave marks at all?
All rifling leaves marks. If it didn't, then it wouldn't spin the bullet at all.
Yes but they lacking for individual marks like a normal barrel. They will know its possible a Glock but thats it. Oiling some bullets with a polishing compound and blasting a few 100s and its done
>Steel wool may be too soft to do the job, but something like sand, lapping compound, grinding dust, etc? Absolutely, that would work.
I recall one case where someone successfully did something like this my ramming some kind of metal tool through the barrel. It apparently made side by side match impossible. Unfortunately for this fuck stick the incident was only used to demonstrate his attempt to cover up the murder and was ultimately important evidence or planning and premedatation so it made a murder 1 conviction easier.
Thats why polishing compound. Just say its for barrel tuning
>some kind of metal tool through the barrel
A file or a drill bit would do the job.
Interesting tidbit: About 20 years ago (ish, I don't remember exactly) Paladin Press published a book which was basically about how to commit the perfect murder/assasination. The tldr was basically: surprise the victim, shoot them several times at close range, leave the scene, then immediately brush out the gun barrel with sand in order to deny the opportunity for a ballistic match, then ditch the gun. A bunch of people raised a big stink about it, and they were forced to stop selling the book. As a fuck you to the judge who ordered the stop sale order they instead gave away the remaining copies they had and made the electronic version free to download from their site. so yeah, this is a well known method.
ain't gonna fly. You need a pretty serious abrasive to fuck up the markings enough to thwart a match, and nobody uses abrasive that coarse for lapping a barrel. Remember, you have to either remove enough metal to erase existing marks, or you have to create new ones which radically obscure existing ones. "polish" ain't gonna do it. you need something that will cut aggressively.
So, all in all, I guess I'll just use a shotgun then.
>Rob convenience store for gum
Was that a Baby Driver reference?
Asking a friend whos living far away for a barrel swap
>The barrel is hard steel, the bullets are much softer lead or copper.
Hot gas erosion is a thing, though. Do about 10 magdumps, as fast as you can, and you’re probably going to cause some detectable changes to your barrel.
>not shaving your entire body down including eyebrows and eye lashes to be a smooth streamlined operator
>not wearing plywood box shoes to conceal foot size and body weight
>not keeping a shot out barrel to commit crimes with then throwing it in a swamp.
>not picking up range brass with fudds finger prints wearing latex gloves to spread out at the scene
>not stealing piles of human hair from the barber shop floor to make it rain on your victims corpse
>not using a garden pesticide jug to spray the room with bleach
lol jfc dude
Why not simply use a different barrel which gets discarded or melted afterwards?
Sure, there's a chance that might work, but why risk it when you can just brush a handful of sand down the barrel and be 100% sure?
How about this:
Go to the range, get handful of bullets from backstop and put them in a shotgun with a fitting sabot.
>Paladin Press
I read that book.
Ballistic forensics is a pseudo science like the polygraph but for some reason it's treated like a DNA test. If you put 100 factory fresh G19s in a line and had all their bullets tested, unless there was some obvious unique defect from botched manufacture it would be impossible to match up the bullets and the guns.
That's exactly what the book I referred to recommended.
The sand thing was a temporary measure you were to undertake immediately after the shooting, but before you had a chance to destroy or dispose of the barrel. The two are not mutually exclusive.
also, if you're fleeing the scene of a crime and need to cover your tracks, which is easier to do without drawing more attention to yourself: magdumping a few hundred rounds, or brushing out the barrel with sand?
>implying 100 factory fresh G19s wouldn't have a single obvious unique defect from botched manufacture
This. Look hard enough and you'll find that every one is unique.
is pretty correct. This evidence is pretty sketchy and will usually be kept out of court. What it can, and is probably more valuable for however, is for police to use while questioning you and putting pressure on you in order to try and elicit a confession. So never answer any questions without a lawyer.
But that's not >this at all, I was mostly making a cheap shot at Glock QC.
Most of the Glocks (the ones without a specific nick or burr) will be about as close to each other as the same barrel is to itself a few hundred rounds later, so "looking hard enough" won't help.
Thanks for the hearty kek mr psychopath
>Go to the range, get handful of bullets from backstop
Go the day after a reserved LE range day.
Didn't it turn out that that book was written by a bored housewife obsessed with true crime stories? I believe it was called 'Hitman: A guide for independent contractors' or something like that.
Could be? I remember reading the book, and the media stink about it at the time (which, ironically, is how I came to hear about it). It wouldn't surprise me though; Paladin Press published an awful lot of SoF style bullshit.
You use a revolver so it doesn't kick out spent cartridges and when you're done you swab the barrel with something abrasive on a rotary tool, like 2K-5K grit sandpaper. Works like a charm.