# Can you trace bullets like fingerprints?



## arnieisblack (Sep 24, 2022)

Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


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## Leo123 (Sep 24, 2022)

As I understand it, from being a TV detective, they can match 2 bullets by the rifling marks they leave on the bullets.  That way they can tell the bullets came from the same gun but, without the gun they can't trace those bullets back to the gun that fired them.  Unless there is some 'rifling' data base I don't know about.  Criminals use stolen guns that can't be traced to them typically.


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## arnieisblack (Sep 24, 2022)

So how could the Coen Bros not know that? Is this a fairly new advanced thing? That movie came out about a decade ago or so? Not really sure, how do you explain on movies when the good guy is killing people with a registered gun? now if it's something like Goodfellas they would be using illegal guns anyways.


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## OhPleaseJustQuit (Sep 24, 2022)

Leo123 said:


> As I understand it, from being a TV detective, they can match 2 bullets by the rifling marks they leave on the bullets.  That way they can tell the bullets came from the same gun but, without the gun they can't trace those bullets back to the gun that fired them.  Unless there is some 'rifling' data base I don't know about.  Criminals use stolen guns that can't be traced to them typically.


You're a TV detective?


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## Leo123 (Sep 24, 2022)

arnieisblack said:


> So how could the Coen Bros not know that? Is this a fairly new advanced thing? That movie came out about a decade ago or so? Not really sure, how do you explain on movies when the good guy is killing people with a registered gun? now if it's something like Goodfellas they would be using illegal guns anyways.


In the movies the 'good guy' is killing in self defense or, is killing a perp so bad, no one cares......I guess....


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## Leo123 (Sep 24, 2022)

OhPleaseJustQuit said:


> You're a TV detective?


Not what I meant.   I meant I get my detective knowledge from TV and movies.  I am not a real detective.


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## OhPleaseJustQuit (Sep 24, 2022)

Leo123 said:


> Not what I meant.   I meant I get my detective knowledge from TV and movies.  I am not a real detective.


Dang!  I was going to ask if you could get me Columbo's autograph.


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## Baron Von Murderpaws (Sep 24, 2022)

Some bullets........depending on the manufacturer............can have engraved numbers on them and are tracable back to who bought that particular package with that bullet in it.

Some ammo has stamped images that are the copyright of the manufacturer, and can be traced through that line.

But I'd say most ammo has to be traced back to the weapon that used it, as every gun leaves different markings on the bullets when fired.

Or so I've been told.


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## Leo123 (Sep 24, 2022)

OhPleaseJustQuit said:


> Dang!  I was going to ask if you could get me Columbo's autograph.


No......But.......'Just one more question'


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## johngaltshrugged (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


The only rifle I recall him using was against the antelope at the very beginning.
You can match ballistics through the rifling (twisting) of the barrel of the rifle but that wasn't applicable since it was used for hunting purposes only.

Otherwise, he bought & used a shotgun.
A rifle is different than a sho gun in that here are no ballistic matches on shotgun pellets because there is no rifling of the barrel to make the necessary markings.


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## Concerned American (Sep 24, 2022)

arnieisblack said:


> So how could the Coen Bros not know that? Is this a fairly new advanced thing? That movie came out about a decade ago or so? Not really sure, how do you explain on movies when the good guy is killing people with a registered gun? now if it's something like Goodfellas they would be using illegal guns anyways.


It all depends on how deformed the bullet is, but the forensic examination of bullets and matching them to the firearm used has been used for at least forty years.  But, as Leo said, if they don't have the gun, they can't match it.


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## OhPleaseJustQuit (Sep 24, 2022)

Is the new sock planning on shooting somebody?


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## arnieisblack (Sep 24, 2022)

Yeah but in the movie he did fire at the bad guy towards the end of the movie. Didn't he know the police could track it? They wouldn't just not care b/c it's a bad villain, they still do their job. At least most cops do.


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## JGalt (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.



I always cast my bullets out of ice, so they melt and can't be traced back to me.

Sometimes I put cherry-flavored Kool-Aid in them, so I can suck on them when I'm not shooting people.

File:WaySniper5.jpg - Internet Movie Firearms Database - Guns in Movies, TV and Video Games


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## arnieisblack (Sep 24, 2022)

Concerned American said:


> It all depends on how deformed the bullet is, but the forensic examination of bullets and matching them to the firearm used has been used for at least forty years.  But, as Leo said, if they don't have the gun, they can't match it.


HBO doc that came out in 2017 said they don't need the gun.


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## Concerned American (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


Didn't Benicio Del Toro use some kind of compressed air rig to kill the first victims in that movie?


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## evenflow1969 (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


Can't be traced back to the rifle with out taking samples of bullets from the rifle.


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## Leo123 (Sep 24, 2022)

JGalt said:


> I always cast my bullets out of ice, so they melt and can't be traced back to me.
> 
> Sometimes I put cherry-flavored Kool-Aid in them, so I can suck on them when I'm not shooting people.
> 
> File:WaySniper5.jpg - Internet Movie Firearms Database - Guns in Movies, TV and Video Games


What about glass bullets?


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## JGalt (Sep 24, 2022)

Concerned American said:


> Didn't Benicio Del Toro use some kind of compressed air rig to kill the first victims in that movie?



No, Benicio Del Toro was "The Collector" in Guardians of the Galaxy. I think.


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## OhPleaseJustQuit (Sep 24, 2022)

evenflow1969 said:


> Can't be traced back to the rifle with out taking samples of bullets from the rifle.






Thinks he came up with something profound.


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## Concerned American (Sep 24, 2022)

JGalt said:


> I always cast my bullets out of ice, so they melt and can't be traced back to me.
> 
> Sometimes I put cherry-flavored Kool-Aid in them, so I can suck on them when I'm not shooting people.
> 
> File:WaySniper5.jpg - Internet Movie Firearms Database - Guns in Movies, TV and Video Games


LOL, we have big assed ice-cycles up here.  I just run my victims through with 'em--no weapon, no evidence.  Wait for spring and bury the corpse.  Frozen all winter, no muss no fuss.


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## arnieisblack (Sep 24, 2022)

It wasn't him it was Javier Bardem.


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## OhPleaseJustQuit (Sep 24, 2022)

Concerned American said:


> LOL, we have big assed ice-cycles up here.  I just run my victims through with 'em--no weapon, no evidence.  Wait for spring and bury the corpse.  Frozen all winter, no muss no fuss.


Somewhere I read something about someone who killed somebody by jamming snow down their throat, blocking their trachea.  By the time the snow melted, deadness.


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## JGalt (Sep 24, 2022)

Concerned American said:


> LOL, we have big assed ice-cycles up here.  I just run my victims through with 'em--no weapon, no evidence.  Wait for spring and bury the corpse.  Frozen all winter, no muss no fuss.



That seems like a waste of good meat. We plant 'em up to their necks in the garden and harvest them in the Fall.


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## Concerned American (Sep 24, 2022)

JGalt said:


> No, Benicio Del Toro was "The Collector" in Guardians of the Galaxy. I think.


My mistake--I'll have to watch that movie again.  I have it confused with another.


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## JGalt (Sep 24, 2022)

OhPleaseJustQuit said:


> Somewhere I read something about someone who killed somebody by jamming snow down their throat, blocking their trachea.  By the time the snow melted, deadness.



You can do the same thing by by forcing water down their throat, then putting them in the freezer. By the time the water freezes, deadness. But it's a little slower.


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## Concerned American (Sep 24, 2022)

OhPleaseJustQuit said:


> Somewhere I read something about someone who killed somebody by jamming snow down their throat, blocking their trachea.  By the time the snow melted, deadness.


That would work too.  LOL


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## evenflow1969 (Sep 24, 2022)

OhPleaseJustQuit said:


> View attachment 701127
> 
> Thinks he came up with something profound.


Lol, not profound. That is something not seen nor understood by the common person. You being a retard is blatantly obvious.  Hilarious 😂 😃 😄 😁 🤣


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## candycorn (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


Well, if you buy a box of bullets at a store, the gunpowder can have identifiers placed into it. Tie the identifiers to a lot#.  Keep track of who buys what lot number...    I'm sure there will be some constitutional challenge to this because as we all know, when gun nuts want to, they can expand the constitution to cover anything


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## OhPleaseJustQuit (Sep 24, 2022)

evenflow1969 said:


> Lol, not profound. That is something not seen nor understood by the common person. You being a retard is blatantly obvious.  Hilarious 😂 😃 😄 😁 🤣


Wow.  there's that very meaningful word again.  Have you ever counted the number of times in a single day that you have used that word, hoping that you could hurt someone's feelings with it?

You'll have to get some new material if you plan on actually insulting me.

Good luck.


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## HereWeGoAgain (Sep 24, 2022)

Leo123 said:


> As I understand it, from being a TV detective, they can match 2 bullets by the rifling marks they leave on the bullets.  That way they can tell the bullets came from the same gun but, without the gun they can't trace those bullets back to the gun that fired them.  Unless there is some 'rifling' data base I don't know about.  Criminals use stolen guns that can't be traced to them typically.



There is a question on whether or not there is a database on the rifling of new firearms.
When you buy a new gun you often get an empty shell casing with it. They say it's just to show the firearm has been tested.
   But is it the only round fired through it? Of course they can check the ballistics on the slug but they also check the empty casing for extraction marks and the firing pin mark.


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## HereWeGoAgain (Sep 24, 2022)

The barrel marks can easily be changed by slightly deforming the rifling by dragging or pushing something down the barrel thats hard enough to deform the rifling.
  Same goes for extractor marks and firing pin marks.


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## evenflow1969 (Sep 24, 2022)

OhPleaseJustQuit said:


> Wow.  there's that very meaningful word again.  Have you ever counted the number of times in a single day that you have used that word, hoping that you could hurt someone's feelings with it?
> 
> You'll have to get some new material if you plan on actually insulting me.
> 
> Good luck.


Don't need new material.  Retard is the perfect description for you. If it ain't broke Don't fix it.


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## Likkmee (Sep 24, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


Yes and no. I was asked to testify in a case...so, being me, I fucked with them.
I had 3 barrel blanks, from one 10' bar stock, rifled by Harry McGowan. The same button was used to rifle them.

The piglets had their meathead  push several bullets through each blank, take the bullets to THE LAB  and, of course, they couldn't tell which bullets came from which barrel.
The judge was irate.
I exsersplained to the dumb motherfucker that a dozen guns in order( by serial number) would have probably been pulled or broached with the same button or tooling and the balistics would be too similar to differentiate.
You could be 90+ % sure a bullet came from a specific piece with those tests(as long as the bullet didn't smash a bone, or a car door or or or...is it enough evidence alone to pluck a bullet from a corpse to put a dual citizen(insert slur here) in the Lincoln chair on it's own ?
You be the judge( pun much)   

ADVICE to future hit men: When you buy, buy 3-4 with consecutive serial numbers


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## Leo123 (Sep 24, 2022)

HereWeGoAgain said:


> The barrel marks can easily be changed by slightly deforming the rifling by dragging or pushing something down the barrel thats hard enough to deform the rifling.
> Same goes for extractor marks and firing pin marks.


Will you have to kill me now?


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## HereWeGoAgain (Sep 24, 2022)

Leo123 said:


> Will tou have to kill me now?



Only if you talk.


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## Leo123 (Sep 24, 2022)

HereWeGoAgain said:


> Only if you talk.


In the words of Sgt. Schultz  (Hogan’s Heros). I KNOW NOTHING!


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## arnieisblack (Sep 25, 2022)

So do forensics need the exact gun to prove it was fired or can they do it with bullets alone?


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## arnieisblack (Sep 25, 2022)

Watch this and see if it's right.


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## arnieisblack (Sep 25, 2022)

Does it just let them know what kind of gun it is or does it trace back to the exact gun owned by the owner?


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## arnieisblack (Sep 25, 2022)

Can they basically trace it back to the gun owner without having the gun or the murder weapon aka gun on their hands?


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## Anathema (Sep 25, 2022)

HereWeGoAgain said:


> There is a question on whether or not there is a database on the rifling of new firearms.
> When you buy a new gun you often get an empty shell casing with it. They say it's just to show the firearm has been tested.
> But is it the only round fired through it? Of course they can check the ballistics on the slug but they also check the empty casing for extraction marks and the firing pin mark


This is something that was done by several states for a period of time. They forced manufacturers to include fired casings and bullets for the state police to include in their databases for potential forensic comparison. 

I think all the states that were doing it have stopped since it proved to be absolutely useless. No crimes were solved this way and the states found it annoying to have to catalog all the ammunition. Besides, most intelligent gun owners simply bought a new barrel for their gun, making the previously catalogued ammunition irrelevant.


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## arnieisblack (Sep 25, 2022)

Anathema said:


> This is something that was done by several states for a period of time. They forced manufacturers to include fired casings and bullets for the state police to include in their databases for potential forensic comparison.
> 
> I think all the states that were doing it have stopped since it proved to be absolutely useless. No crimes were solved this way and the states found it annoying to have to catalog all the ammunition. Besides, most intelligent gun owners simply bought a new barrel for their gun, making the previously catalogued ammunition irrelevant.


Do you know if it's based on facts? Be honest.


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## HereWeGoAgain (Sep 25, 2022)

arnieisblack said:


> So do forensics need the exact gun to prove it was fired or can they do it with bullets alone?



Of course you need the gun.
Ya gotta have something to compare it to.


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## Blues Man (Sep 25, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


If all you have is the slug and it's in good enough condition you can match the marks left from the barrel rifling with the gun it was fired from if you have the gun.

Sometimes the composition of the bullet can be traced to a particular manufacturer.
If you have the shell casing you can also match that to the gun that fired it because the firing pin leaves unique marks like a barrel and the shell casing will make it easy to find the manufacturer and maybe even the batch and where it may have been sold.


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## HereWeGoAgain (Sep 25, 2022)

Anathema said:


> This is something that was done by several states for a period of time. They forced manufacturers to include fired casings and bullets for the state police to include in their databases for potential forensic comparison.
> 
> I think all the states that were doing it have stopped since it proved to be absolutely useless. No crimes were solved this way and the states found it annoying to have to catalog all the ammunition. Besides, most intelligent gun owners simply bought a new barrel for their gun, making the previously catalogued ammunition irrelevant.



   I know the last revolver I bought didnt come with the empty casing.
The AR did though.


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## Anathema (Sep 25, 2022)

arnieisblack said:


> Do you know if it's based on facts? Be honest.


Yes. This was the law in NY, MD and I believe a couple other states for nearly a decade. Both NY and MD ended the practice because it was in effective. I know NY gun owners who replaced pistol barrels immediately upon purchasing guns during that period of time.

If you’re getting an empty casing with a pistol now, it may be a “proof of function” item. Essentially a proof thst the gun was functioning when it left the factory.


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## Anathema (Sep 25, 2022)

HereWeGoAgain said:


> Of course you need the gun.
> Ya gotta have something to compare it to.


They need the exact gun to make a 100% match. The FBI keeps records for general comparison from pretty much every model of firearm commercially available in the USA and has for decades.


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## 2aguy (Sep 25, 2022)

Leo123 said:


> As I understand it, from being a TV detective, they can match 2 bullets by the rifling marks they leave on the bullets.  That way they can tell the bullets came from the same gun but, without the gun they can't trace those bullets back to the gun that fired them.  Unless there is some 'rifling' data base I don't know about.  Criminals use stolen guns that can't be traced to them typically.




But only for a while....repeated firing of the rifle will change the marks in the barrel through friction...just like treads on a tire....right?


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## Concerned American (Sep 25, 2022)

arnieisblack said:


> Does it just let them know what kind of gun it is or does it trace back to the exact gun owned by the owner?


I don't think it can trace back to the gun---unless they have the gun.  They have to have something to match the bullet/casing  to.  It seems to be a really good tool to tie multiple crimes together by examining the casings/bullets but until they have the gun used it is impossible to tie the two together.  You can have 100 bullets with the same rifling marks or 100 casings with the same bolt, firing pin or extractor marks, but if you don't have the gun that made the marks it is limited.


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## arnieisblack (Sep 25, 2022)

So you got the bullet remnants and if it's registered they can match it to the gun they don't have?I'm so confused.


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## HereWeGoAgain (Sep 25, 2022)

arnieisblack said:


> So you got the bullet remnants and if it's registered they can match it to the gun they don't have?I'm so confused.



It's simple.
If they did fire the gun before they sold it and put the ballistic results in a database it could be matched to the gun even if it's not in their possession. 
  They could then go back and find out who purchased that weapon.
 It's not rocket surgery.


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## Concerned American (Sep 25, 2022)

arnieisblack said:


> So you got the bullet remnants and if it's registered they can match it to the gun they don't have?I'm so confused.


Nope, they can't match it to any gun until they have the gun.  But---they can match bullets and casings from seemingly unrelated crimes that used the same gun and when they do get the gun, they can tie it all together.


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## Concerned American (Sep 25, 2022)

HereWeGoAgain said:


> It's simple.
> If they did fire the gun before they sold it and put the ballistic results in a database it could be matched to the gun even if it's not in their possession.
> They could then go back and find out who purchased that weapon.
> It's not rocket surgery.


Or brain science.  LOL


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## arnieisblack (Sep 26, 2022)

Do you think it would be a good idea to just ban all guns? It worked in Australia.


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## HereWeGoAgain (Sep 26, 2022)

arnieisblack said:


> Do you think it would be a good idea to just ban all guns? It worked in Australia.



Absolutely not.
We don't care what Australians do or any other country for that matter..
   Look what happened to Venezuela,they took their firearms and 4 years later they were shooting down their own citizens in the streets. 
When a country want to ban citizens from owning firearms you can bet that government is about to do something those citizens aren't going like.


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## Concerned American (Sep 26, 2022)

arnieisblack said:


> Do you think it would be a good idea to just ban all guns? It worked in Australia.


NOPE


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## Esdraelon (Sep 27, 2022)

Toffeenut Baconsmuggler said:


> Some bullets........depending on the manufacturer............can have engraved numbers on them and are tracable back to who bought that particular package with that bullet in it.
> 
> Some ammo has stamped images that are the copyright of the manufacturer, and can be traced through that line.
> 
> ...


Most guns will have a spent casing included in the case to show that a round has been fired and the rifling marks recorded.


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## M14 Shooter (Sep 27, 2022)

arnieisblack said:


> Do you think it would be a good idea to just ban all guns? It worked in Australia.


No.
And no, they didn't.


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## HereWeGoAgain (Sep 27, 2022)

Esdraelon said:


> Most guns will have a spent casing included in the case to show that a round has been fired and the rifling marks recorded.



We discussed that earlier in this thread.
I've purchased several guns that had the spent casing in the box but lately there hasnt been one.
  I wouldnt begin to believe they didnt shoot it and added the results to a database they just dont leave the casing in the box anymore.


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## beautress (Oct 23, 2022)

arnieisblack said:


> Can someone explain it to me how the police can trace bullets like fingerprints? And can you do it without the actual gun? Reason I'm asking is b/c in No Country For Old Men, lewelyn has a rifle and he's t he g ood guy,kinda. So why would he have a rifle to fight the bad guys when it could trace back to him? Many movies are like this.


Here ya go, arnieisblack:
​


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## whitehall (Oct 25, 2022)

If he has the weapon, a skilled ballistics investigator can make a comparison between a fired slug found at the scene of a crime and a freshly fired bullet. The lands and grooves have distinct markings from minute imperfections in every barrel. It's not just the marks but the relationship to each other in the comparison like fingerprints. A ballistic investigator can also determine what kind of weapon based to the dimensions of the lands and grooves and the twist in the rifling. firing pin marks in an expended cartridge can also be compared with reasonable accuracy.


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## Jarlaxle (Oct 27, 2022)

It's not real. Ballistic "fingerprints" are a fantasy. Identify a caliber, sure. Rule OUT a gun, maybe. Identify a model of pistol...possibly. (Offhand, Colt and Smith and Wesson use different rifling.) Identify a specific gun? No.


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## WinterBorn (Oct 27, 2022)

OhPleaseJustQuit said:


> Dang!  I was going to ask if you could get me Columbo's autograph.



If you want Columbo's autograph, you need a Medium, not a detective.


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## whitehall (Oct 27, 2022)

Jarlaxle said:


> It's not real. Ballistic "fingerprints" are a fantasy. Identify a caliber, sure. Rule OUT a gun, maybe. Identify a model of pistol...possibly. (Offhand, Colt and Smith and Wesson use different rifling.) Identify a specific gun? No.


Don't take up a life of crime if you think ballistics is a fantasy. While there apparently is no data base of firearms, it's easy for a ballistics expert to make a comparison if he has the weapon and the fired bullet. Firing pin impressions in a shotgun shell. The rate of twist on a fired bullet. They are all part of ballistic evidence.


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## Jarlaxle (Oct 27, 2022)

whitehall said:


> Don't take up a life of crime if you think ballistics is a fantasy. While there apparently is no data base of firearms, it's easy for a ballistics expert to make a comparison if he has the weapon and the fired bullet. Firing pin impressions in a shotgun shell. The rate of twist on a fired bullet. They are all part of ballistic evidence.



CSI is not real. The rifling marks on my wife's pistol are identical to the previous 50 and next 50 barrels on the line. (Source: gunsmith who has testified in Federal court as an expert witness.) My S&W Model 29 is on at least its third barrel, and I suspect the markings now are different from the markings when the barrel was new. CSI is TV, not reality.

I will give you a trillion dollars if you can compare rifling marks from a round from my uncle's target rifle to anything. (The rounds from it-spinning 500,000+RPM and traveling ~4000fps-disintegrate on impact.)


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## whitehall (Oct 27, 2022)

Jarlaxle said:


> CSI is not real. The rifling marks on my wife's pistol are identical to the previous 50 and next 50 barrels on the line. (Source: gunsmith who has testified in Federal court as an expert witness.) My S&W Model 29 is on at least its third barrel, and I suspect the markings now are different from the markings when the barrel was new. CSI is TV, not reality.
> 
> I will give you a trillion dollars if you can compare rifling marks from a round from my uncle's target rifle to anything. (The rounds from it-spinning 500,000+RPM and traveling ~4000fps-disintegrate on impact.)


The science of ballistics is real and verified in a hundred years of court cases.  Some rounds disintegrate on impact and aren't suitable for ballistic comparison but they can sometimes reveal the caliber and sometimes the vintage of the round based on the chemical composition and weight. I worked with a ballistic expert years ago and I can promise you that they can match up an individual slug from a weapon that seems identical to a thousand others. Every weapon that has been fired leaves traces of deposits in the barrel and each of these deposits leaves a minute mark on the recovered bullet that can be compared to a fresh round from the weapon.


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## Jarlaxle (Oct 27, 2022)

whitehall said:


> The science of ballistics is real and verified in a hundred years of court cases.  Some rounds disintegrate on impact and aren't suitable for ballistic comparison but they can sometimes reveal the caliber and sometimes the vintage of the round based on the chemical composition and weight. I worked with a ballistic expert years ago and I can promise you that they can match up an individual slug from a weapon that seems identical to a thousand others. Every weapon that has been fired leaves traces of deposits in the barrel and each of these deposits leaves a minute mark on the recovered bullet that can be compared to a fresh round from the weapon.



If I fired a round from my Model 29, ran a steel file through the barrel, and fired another round, the rifling would not match. (Even if the rounds remained intact, which they usually do not.) Most rifle rounds fragment on impact. Rounds from my uncle's target rifle don't fragment-they disintegrate, to the point I doubt even the CALIBER could be determined with any certainty. (Like most high-velocity rifles firing lead rounds.)

Bite mark analysis was "verified" in many cases...until it was shown to be mostly bullshit.


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## whitehall (Oct 28, 2022)

Jarlaxle said:


> If I fired a round from my Model 29, ran a steel file through the barrel, and fired another round, the rifling would not match. (Even if the rounds remained intact, which they usually do not.) Most rifle rounds fragment on impact. Rounds from my uncle's target rifle don't fragment-they disintegrate, to the point I doubt even the CALIBER could be determined with any certainty. (Like most high-velocity rifles firing lead rounds.)
> 
> Bite mark analysis was "verified" in many cases...until it was shown to be mostly bullshit.


You can deface all your firearms with files and metal rods but it would make the next round fired from an altered barrel easier to match with a fired slug.


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## JohnDB (Nov 21, 2022)

Most people who commit assault crimes using guns aren't exactly the brightest bulbs on the tree.  

Currently, those who own firearms are usually watching out for the BATF and trying to avoid their attention.   Many of your gun enthusiasts are machinists in training.   Files, drills, bores and etc can change the "signature" of any firearm that possibly got left on any round or cartridge the firearm came into contact with.  

You can change everything from a receiver characteristics to a firing pin pattern and Barrel in a matter of minutes.  It isn't difficult or labor intensive.  Guns aren't rocket science by any stretch of the imagination.   

Guns aren't magic...they aren't unchangeable or difficult to modify.  

However,  for the ne'er-do-wells of our society they haven't got a clue how to do any of these things.  They usually keep their guns AFTER committing serious assault crimes in locations that lead police straight back to themselves.   (If the police detectives bother themselves that much) 

Most crimes are committed by using stolen guns to begin with...meaning they already committed a crime by stealing the firearm instead of legally obtaining it.


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## Bob Blaylock (Nov 21, 2022)

Leo123 said:


> As I understand it, from being a TV detective, they can match 2 bullets by the rifling marks they leave on the bullets.  That way they can tell the bullets came from the same gun but, without the gun they can't trace those bullets back to the gun that fired them.  Unless there is some 'rifling' data base I don't know about.  Criminals use stolen guns that can't be traced to them typically.



  My understanding is that that's not at all reliable, if enough bullets have been fired from the same gun, between the two that are being matched.  Every bullet wears the bore, and changes the pattern of scratches and marks that that barrel leaves on subsequent bullets.  Perhaps even some corrosion effects as well.

  If two bullets are found at the same crime scene, I think they can reliably determine if they were fired from the same gun.

  If they get their hands on a gun that they suspect to have been used in a crime years ago, but which has since been fired enough times since then, I do not think that they can match it with a bullet from that crime scene.


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## Bob Blaylock (Nov 21, 2022)

Esdraelon said:


> Most guns will have a spent casing included in the case to show that a round has been fired and the rifling marks recorded.



  Depending, I suppose, on the precision and consistency with which they are manufactured, I would expect that any brand-new gun would be an almost exact ballistic match for every other brand new gun of that same make and model.  Perhaps even with other models that use the same barrel.

  I wouldn't expect any gun to develop any unique, identifiable _“fingerprint”_, until enough bullets have been fired through it to wear it in some way different than how other similar guns have been worn.


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## Leo123 (Nov 21, 2022)

Bob Blaylock said:


> My understanding is that that's not at all reliable, if enough bullets have been fired from the same gun, between the two that are being matched.  Every bullet wears the bore, and changes the pattern of scratches and marks that that barrel leaves on subsequent bullets.  Perhaps even some corrosion effects as well.
> 
> If two bullets are found at the same crime scene, I think they can reliably determine if they were fired from the same gun.
> 
> If they get their hands on a gun that they suspect to have been used in a crime years ago, but which has since been fired enough times since then, I do not think that they can match it with a bullet from that crime scene.


Good points.   Eventually, after many firings, the lans and grooves could change.   At that point the person evaluating the bullets and their experience would have to come into play and the final decision would be up to a jury.   Besides, lans and grooves in bullets would just be one part of Prosecution discovery.  If lans and grooves were the ONLY evidence it could get complicated and harder to prove.


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