How traceable are bullets?


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Fosbery
July 6, 2009, 09:34 AM
Is it possible to link a bullet to a specific gun, other than simply matching calibers? For instance, from the rifling marks on the bullet?

I'm pretty sure it's not, but wanted to check.

Is there such a thing as a ballistics database in the US or certain states?

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Kleanbore
July 6, 2009, 09:36 AM
It is.

Blackbeard
July 6, 2009, 09:55 AM
They match rifling marks by comparing two bullets - one found at the scene and a test round fired from a specific gun -- if they match then they know the same gun fired both bullets. I'm not aware of a rifling marks database that would let you "look up" what gun fired a given bullet. If there were such a database it'd be useless if the gun's owner ever changed barrels.

Sam1911
July 6, 2009, 10:10 AM
Is it possible to link a bullet to a specific gun, other than simply matching calibers? For instance, from the rifling marks on the bullet?

To a degree, yes. If a fired bullet is recovered at a crime scene (for example) that is still in good enough condition to observe the rifling marks, it can be compared to a bullet fired from a specific firearm to see if the rifling marks match. Like finger-printing, this is more of an art than a science, and it depends on matching the number of similarities between the marks on the two bullets to establish a probablility that they were fired from the same gun. There is no "certainty" to it.

Several problems exist with the technique: For one, the rifling in the bore of a firearm changes as it wears. The more firings take place between the two test bullets, the less alike the marks will be = probability goes down. As pointed out, if the owner replaces the barrel, all bets are off.

The bigger problem comes in simply having test material. To do this, you'd need a recovered bullet in fairly decent condition. The more smashed/deformed the slug is, the harder identification will be (even less probability of a match). And, you need to have the rifle or pistol you suspect fired the round in hand so you can run the control test and recover the comparison bullet.

Simply having the recovered slug from a crime scene gets you little beyond knowing the caliber, weight (assumed, from what's left), and possibly the make of gun it was fired through (Polygonal or cut rifling? Number of lands & grooves, etc.). Without a suspect in mind, and his gun in custody to test, there's no way to use the fired slug as a "signature" to ID the shooter, or even the owner of the gun.

Is there such a thing as a ballistics database in the US or certain states? No. Some states (MD) have (or had) maintained "ballistics fingerprint" records on all handguns sold. But, to my knowledge, these only kept fired cartridge cases -- not recovered bullets. The idea being that the fired cases bear the markings of the firing pin, extractor, ejector, and whatever impact marks the gun makes on the case as it cycles. Then the cases on file could be compared against cases recovered at crime scenes. The same issues of uncertainty apply to this as to the bullet "fingerprinting," of course.

Information I've read indicates that many millions of dollars have been spent to build and maintain these databases/archives, and they've yet to be used conclusively in ONE criminal trial.

-Sam

P.S. -- Fortunately, on television, this is a valuable and reliable set of tests that puts the bad-guy behind bars in 30 minutes or less, every week! ;-)

chuckusaret
July 6, 2009, 10:21 AM
I'm not aware of a rifling marks database that would let you "look up" what gun fired a given bullet. If there were such a database it'd be useless if the gun's owner ever changed barrels.

I thought Maryland required a spent bullet be provided to the state by the gun manufacturers on all guns sold in the state. I also heard that this program, the cost is in the millions per year, had not assisted in solving any shooting cases.

Could someone from Maryland reply please or has anyone else heard of this requirement. I attempted to find the Md. law but to no avail.

loadedround
July 6, 2009, 10:41 AM
Chuck: I my memory serves me correctly, Maryland quietly dropped dropped this law a short time ago. It was costing them many millons of dollars yearly and had not yet solved any crime, nor lending any clues to crime. Just another "feely good" liberal law that never worked. :)

heron
July 6, 2009, 10:51 AM
It was just a few nights ago, on CSI Miami, they took a bunch of tiny, tiny bullet fragments from some victim's body, and scanned them, and a computer put them all together like a jigsaw puzzle, and they got a match . . . and I think those people actually DO have a database of rifling marks!

well, hey, it must be true, it was on TV!

<snark off>

nitetrane98
July 6, 2009, 10:51 AM
Several problems exist with the technique: For one, the rifling in the bore of a firearm changes as it wears. The more firings take place between the two test bullets, the less alike the marks will be = probability goes down.

Just to illustrate that, I heard somewhere that the Mannlicher Carcano rifle used to kill JFK has been fired so many times after the fact by the "experts", trying to determine if the rate of fire could be matched etc, that it now could not be proven that it was the gun used to kill JFK based on ballistic matching.

lebowski
July 6, 2009, 10:53 AM
I believe NY (not sure if it's NY State or NYC) has or had a program for ballistic fingerprinting. My understanding is the program was a massive failure - they spent millions of dollars, fingerprinted tens of thousands of firearms, and the program has helped solve exactly zero crimes.

I read about it on wikipedia, so take that for what it's worth. I can't find the article now.

bigalexe
July 6, 2009, 10:54 AM
How traceable are bullets?

Well if the bullets have a bit of Phosphorus or other incendiary in the back of them they are immediately traceable to the source provided you are on the right angle.

isp2605
July 6, 2009, 10:55 AM
There is a national database but mostly of fired cases. It's been operational for about 15 yrs. It works sort of like AFIS which is the fingerprint database. Fired cases are entered into the database. Then cases recovered from a crime scene can be scanned into the system and the computer will check that case with cases in the system. What that will do is link a gun used in Shooting A with Shooting B.

moooose102
July 6, 2009, 11:09 AM
yes, it is possible to match a bullet to a gun, providing they have the gun to compare it to. but, it is also possible to alter the barrel so it shoots a bullet so it no longer matches how it used to. it is not all that hard on a pistol, but a rifle would be much more difficult. i will not go into it, because i do not want to give anybody directions, but a little imagination would go a long way. i had never thought about it until i looked at the inside of one of my pistol barrels with an eye loupe. do that, and it will almost become self evident on what and how to do it.

I believe NY (not sure if it's NY State or NYC) has or had a program for ballistic fingerprinting. My understanding is the program was a massive failure - they spent millions of dollars, fingerprinted tens of thousands of firearms, and the program has helped solve exactly zero crimes.

just like microstamping! a horrible waste of time and money for no real purpose other than making ammo so expensive it will deter shooting all together.

Sam1911
July 6, 2009, 11:19 AM
I thought Maryland required a spent bullet be provided to the state by the gun manufacturers on all guns sold in the state.

I lived in MD up until about 3 years ago, and there was only the fired CASE requirement, nothing about the bullets. And only for handguns.

Maryland quietly dropped dropped this law a short time ago. It was costing them many millons of dollars yearly and had not yet solved any crime, nor lending any clues to crime.I had heard that the MSP was lobbying to have this killed off as well. The number $20 million keeps floating through my memory. That was some years ago, though. I believe that the "ballistic fingerprint" data had been submitted as evidence in something like 4 criminal trials, but was conclusive, instrumental, or enlightening in none of them. Seems the MSP believes they could use $20 million (or whatever) elsewhere and aren't getting much help for the money.
-Sam

Sam1911
July 6, 2009, 11:27 AM
There is a national database but mostly of fired cases. It's been operational for about 15 yrs. It works sort of like AFIS which is the fingerprint database. Fired cases are entered into the database. Then cases recovered from a crime scene can be scanned into the system and the computer will check that case with cases in the system. What that will do is link a gun used in Shooting A with Shooting B.


Do you know where these cases are coming from? Is this a database of cases collected at crime scenes that are then held on file for future matching?

The manufacturers of firearms are certainly not sending sample cases from every gun they make to the government.

Please provide a link that explains this more clearly. Considering that the government doesn't maintain a database of where guns go or who buys them, they certainly aren't "finger-printing" them all, either.

-Sam

Sam1911
July 6, 2009, 11:41 AM
http://www.ocshooters.com/Reports/cobis/ibis.pdf

This is a report on ballistic fingerprinting by MSP's Forensics Sciences Division. A great read (well the first few paragraphs, which is as far as I got through it).

Seems they consider it too flawed to proceed with and completely worthless as far as producing "hits."

They cite New York State's "sister program" which is costing $4 million A YEAR and has not yet produced A hit.

-Sam

isp2605
July 6, 2009, 12:04 PM
Do you know where these cases are coming from? Is this a database of cases collected at crime scenes that are then held on file for future matching?
Most are from crime scenes, recovered firearms, evidence, etc. I believe states that required fired cases were also submitting them to the database but since I never worked with states like Maryland on any cases I don't know what they were submitting.


The manufacturers of firearms are certainly not sending sample cases from every gun they make to the government.
Nope. Like I said it's similiar to AFIS. Not every person in the US is fingerprinted and put AFIS. Same with Drugfire. It's data than comes into the system.


Please provide a link that explains this more clearly. Considering that the government doesn't maintain a database of where guns go or who buys them, they certainly aren't "finger-printing" them all, either.
Do a search on "Drugfire". That's what the FBI called their database. ATF also had a similar database but I can't recall the name of it. I only used Drugfire on my cases.

eye5600
July 6, 2009, 12:30 PM
I've always wondered what would happen if you took 50 sequentially manufactured guns off the line from a good manufacturer (e.g. Colt or S&W) and fired 2 bullets from each, then mixed up the 100 bullets and let a firearms examiner try to pair them up. Public statements on firearms ID suggests that they could be sorted out with no error or minimal error, but more candid comments suggest not.

Of course, in the real world from law enforcement, it can weigh pretty heavily even if the ID only goes to the number of lands and grooves and a match to the construction of the bullets still in the gun. It's like getting the make and model of the car, but not the plate number.

JimmyN
July 6, 2009, 12:36 PM
I have gotten several new firearms that came with a small manilla envelope that contained a fired case from the factory. The envelope was marked with the date, caliber, model and serial # of the handgun. I don't know if they still do, but all new Glock's used to come with a factory fired case.

In VA you received the envelope and fired case with the new firearm, since it serves no purpose, other than a record of when the factory built and test fired your new gun. But if you are in Maryland the FFL dealer that sells you the new firearm turns that envelope over to the State Police for their spent case database. Or at least that is the way it used to work.

41022collector
July 6, 2009, 12:50 PM
Various forensics labs have data bases of bullets and firearms used in crimes. new York and a cpl other states require a certified shot round and the bullet and case kept on file for all firearm sales.

Lead inside of a barrel can be matched to a specific bullet. The bullet lead can be matched with company records of chemical make up. A bullet with decent rifling can be matched to a type of firearm and one the firearm is found can be matched to that bullet.

Ballistics forensics is a wide field and many aspects of it. The FBI prob has the most extensive searchable by LEO request data base in the world. Starting 2010, there will be many matching characteristics of both firearms and ammo. Micro Stamping of firearm serial numbers on firing pins and bolt/breech faces. lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.

Regards,
Mike

isp2605
July 6, 2009, 12:52 PM
Public statements on firearms ID suggests that they could be sorted out with no error or minimal error, but more candid comments suggest not.

It's pretty simple really as long as the items being tested are in useable condition. It's not rocket science. It's nothing more than tool mark identification when comparing things like screwdriver pry marks or any other metal to metal markings. No metal is completely 100% smooth unless it undergoes a lot of polishing which is not the case in firearm manufacture. Such polishing is only done for extreme scientific uses. Any scratches or imperfections on an item when rubbed against another item will leave impressions. In the case of a firearm the barrel with it's imperfections are harder than the bullet materials. When the bullet rubs against the barrel the imperfections on the barrel are transferred to the bullet. Pretty simple then to compare.

Sam1911
July 6, 2009, 01:08 PM
Public statements on firearms ID suggests that they could be sorted out with no error or minimal error, but more candid comments suggest not.

It's pretty simple really as long as the items being tested are in useable condition. It's not rocket science. It's nothing more than tool mark identification ... When the bullet rubs against the barrel the imperfections on the barrel are transferred to the bullet. Pretty simple then to compare.


In a perfect situation, yes. But take the recovered bullet out of an oak tree or plaster wall, where it is highly deformed and the surface it embedded into has caused extensive additional marking and things get a lot harder. (Like you said, a usable sample.) As less and less of the bullet's exterior surface is left pristine, fewer points of comparison can be reliably made. And when you take those few points and compare them to those on bullets fired by two different examples of identical guns, the "paternity test" gets a lot more inconclusive. Put them through a pistol such as a Glock that uses polygonal "rifling" and I would imagine it's yet another step harder to differentiate which gun fired the sample bullet.

So, it's not rocket science in that it isn't all that complicated. But the results are not universally conclusive, either.
-Sam

Sam1911
July 6, 2009, 01:13 PM
Starting 2010, there will be many matching characteristics of both firearms and ammo. Micro Stamping of firearm serial numbers on firing pins and bolt/breech faces. lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.

Which legislation is this that will bring all this new technology? Is there something on the books that will make this reality next year? I keep hearing rumors of legislation being proposed, but it's always shot down as impracticable.

Last I heard we were a LONG way from any of those being possible, so if it will be federally mandated, please let us know!

-Sam

highorder
July 6, 2009, 01:13 PM
I've always wondered what would happen if you took 50 sequentially manufactured guns off the line from a good manufacturer (e.g. Colt or S&W) and fired 2 bullets from each, then mixed up the 100 bullets and let a firearms examiner try to pair them up.

They would (honestly, objectively) NOT be able to tell you anything.

Lead inside of a barrel can be matched to a specific bullet. The bullet lead can be matched with company records of chemical make up.

You DO know that has been debunked, right?

All this stuff falls into the same catagory as the polygraph.

It's sham science used as an interrogation tool, or a case-maker in court.

Sam1911
July 6, 2009, 01:28 PM
Lead inside of a barrel can be matched to a specific bullet..

I've not heard of many folks getting shot these days with unjacketed lead ammo... :scrutiny: And, even if we're dealing with JHPs or FMJ, how would knowing that one gun fired the kind of bullet (jacketed) that was used in a crime (or even the brand of bullet) make for a good prosecution, when there's only a handful of manufacturers and probably 7 out of any 10 guns tested would have copper fouling from either one of them you'd pick?

The bullet lead can be matched with company records of chemical make up Cite, please? Yes, I know they do it on TV. :rolleyes: I want to see a real-world example of a forensics lab using mass spectrometry to link a bullet to a specific manufacturer by alloy composition. And, again, if there's under 10 very common bullet manufacturers, and even allowing that their alloys are consistent enough and distinct enough to repeatably tell one from another (which I doubt), how does this help the prosecution?

Prosecutor -- "Your honor, due to the distinct chemical signature of the fouling in the defendant's gun, we now can conclusively prove that he has fired the same ammo as the bullet which was used to murder the victim! A kind of full-metal-jacketed ammunition known as Winchester "White Box."

Defense -- "Uh, your honor, every gun in the state has had Win. White Box through it..." :D

-Sam

isp2605
July 6, 2009, 01:30 PM
In a perfect situation, yes. But take the recovered bullet out of an oak tree or plaster wall, where it is highly deformed and the surface it embedded into has caused extensive additional marking and things get a lot harder
The recovered bullet doesn't have to be in perfect condition. I've had bullets matched recovered from trees, after going thru wall board and imbedding into 2X4s, after going thru car bodies and interiors. As long as the rifling is completely deformed it can usually be a viable specimen. It does take a whole lot of material.

Put them through a pistol such as a Glock that uses polygonal "rifling" and I would imagine it's yet another step harder to differentiate which gun fired the sample bullet.

One of the internet falacies being spread was bullets from Glocks can't be traced to a specific firearm because of the Glock's polygon bore. Not so. Any metal on metal transfer is enough. There's no rifling on screwdrivers and prybars and we make cases everyday on those tool marks. And barrel-bullet transfer is nothing more than a tool mark. We don't make every case where a pry bar is used either but that doesn't mean it's useless technology. It's not like TV and CSI.
The polygon bore "theory" is the same as the old story of Glocks can't be seen on airport xray machines.

Sam1911
July 6, 2009, 01:42 PM
The recovered bullet doesn't have to be in perfect condition. I've had bullets matched recovered from trees, after going thru wall board and imbedding into 2X4s, after going thru car bodies and interiors. As long as the rifling is completely deformed it can usually be a viable specimen. It does take a whole lot of material.
I think you ment "...the rifling isn't completely deformed..." and "It doesn't take a whole lot of material, right? Makes more sense.

I'm sure you're right. Can you explain more completely how the points of identification work, though? Certainly, two bullets fired from the same gun into test media will not look identical, so how is the "match" made? What percentage of similar markings determines a "hit"?
Or, rather, what degree of certainty will you offer on a given match? Do you only identify a "match" if there's a 95% correlation? Or 50%? 25%?

One of the internet falacies being spread was bullets from Glocks can't be traced to a specific firearm because of the Glock's polygon bore. Not so. Any metal on metal transfer is enough. ... The polygon bore "theory" is the same as the old story of Glocks can't be seen on airport xray machines. Wait a minute, I didn't say Glocks couldn't be ID'd this way. I said it would make it harder, not having distinct rifling impressions. If you say that that isn't the case at all, I'll bow to your experience on the matter.

-Sam

isp2605
July 6, 2009, 01:44 PM
I've not heard of many folks getting shot these days with unjacketed lead ammo...
And you know that because of how exactly?
Actually it's not that uncommon to find all lead bullets in a shooting. There are plenty of all lead ammo being sold and used.

how would knowing that one gun fired the kind of bullet (jacketed) that was used in a crime (or even the brand of bullet) make for a good prosecution, when there's only a handful of manufacturers and probably 7 out of any 10 guns tested would have copper fouling from either one of them you'd pick?
It's all about building a case. Real world cases are nothing like what you see on TV. If we built our cases like you see on TV there would be a whole lot of guilty people walking free.

I want to see a real-world example of a forensics lab using mass spectrometry to link a bullet to a specific manufacturer by alloy composition.
Sure it can be done. It's no different than taking a soil sample, analyzing the composition, then determining where it came from. Same with lead. There are impurities specific to areas and compositions specific to manufacturers. You're right, it's not like on TV so don't believe everything the news reports as not being possible. When the news reported several years ago that bullets couldn't be linked to a manufacturer the news didn't fully report the story or report it accurately. You've got reporters who don't understand what's involved. What a surprise the news got it wrong. What the real story involved was just testing the lead from a bullet and saying the lead came from such and such maker. However, what the news didn't report was it is possible to compare a same to a known sample. That's simple science which is done everyday in labs all over the world.

isp2605
July 6, 2009, 01:51 PM
Can you explain more completely how the points of identification work, though? Certainly, two bullets fired from the same gun into test media will not look identical, so how is the "match" made? What percentage of similar markings determines a "hit"?
Or, rather, what degree of certainty will you offer on a given match? Do you only identify a "match" if there's a 95% correlation? Or 50%? 25%?

You are correct on my typing errors.
It's like anything. The more verifiable points the better. There is nothing that says if we only get 24% that isn't not useable but if we get 25% it is valid. Nothing is 100% nor is it required to be. I know on TV court cases they make every piece of evidence 100% conclusive. It's not. It's about building a case.

I said it would make it harder, not having distinct rifling impressions.
All the Glock polygon rifling does is tell us it's polygon rifling. Glock isn't the only firearm with polygon rifling. It doesn't make it any more difficult. It's still metal on metal transfer. The sharp groove edges isn't what's important for striations. When looking for metal on metal transfer it's the marks left. The rifling only tells us what kind of rifling, number of grooves, twist rate, etc. Comparing striations is just metal on metal contact and rifling doesn't enter into it. Screwdrivers and prybars don't have rifling and those are easy to match. It's sort of like bite marks which are a form of tool marks. Same kind of process. As teeth wear and are chipped the impressions won't be identical but still basic marks are left which can be matched.

Sam1911
July 6, 2009, 01:56 PM
And you know that because of how exactly?
Actually it's not that uncommon to find all lead bullets in a shooting. There are plenty of all lead ammo being sold and used.
If that's what you see in the business, then I can't argue the point. Sure isn't easy to find much in stores, but that doesn't mean it's impossible. (And I was forgetting how much rimfire ammo is sold unjacketed. Plenty of homicide with .22s from what I've read.)

It's all about building a case. Real world cases are nothing like what you see on TV. If we built our cases like you see on TV there would be a whole lot of guilty people walking free.You're saying it's another card in the deck, or the accumulated "preponderance of evidence?" I can see that. Not conclusive in itself, but adding to the heap. O.k.

Sure it can be done. It's no different than taking a soil sample, analyzing the composition, then determining where it came from. Same with lead. There are impurities specific to areas and compositions specific to manufacturers.... it is possible to compare a same to a known sample. Ah, well now we're in total agreement. If you have a known sample of the manufaturer's output (by lot number/batch?) you could match a certain bullet to that batch. Much like matching a recovered bullet's rifling imprint to a suspect's gun -- which you have on hand and can take a sample bullet from.

But are you saying there's an archive of bullet alloys and an investigator can take a recovered bullet, test a sample of it, and look up who made it? Not sure that's realistic.

-Sam

isp2605
July 6, 2009, 02:03 PM
But are you saying there's an archive of bullet alloys and an investigator can take a recovered bullet, test a sample of it, and look up who made it? Not sure that's realistic.
Nope, didn't say that. What can happen is say a bullet is recovered, unknown make. The construction and contents are analyzed. We go to a company, let's say Federal. Federal says yeah, they mixed so much % lead and % tin at such and such temps. They may or may not still have bullets from that same batch which can be compared. We do the same with paint, clothing materials, shoes, tires, etc.

Sam1911
July 6, 2009, 02:09 PM
I comprehend. Thanks for the clarity!

-Sam

stchman
July 6, 2009, 02:15 PM
I personally think hte whole idea of matching up a bullet to a particular barrel would be pretty difficult.

Barrels of rifles, pistols, and revolvers are made by a machine using the same exact dimensions and specifications.

Even if you could "match" a particular round to a particular barrel what if the person shoots the gun again many times? Cleaning the barrel would introduce new scratches and wear marks.

dtrBG
July 6, 2009, 03:13 PM
Barrel
Extractor
Ejector
Firing Pin

All leave a mark, put all of this together and it's a pretty good science :)

isp2605
July 6, 2009, 03:56 PM
I personally think hte whole idea of matching up a bullet to a particular barrel would be pretty difficult.
What you think and what reality is are obviously quite different in this regard.

rondog
July 6, 2009, 03:58 PM
Of course, if you use THESE, there will be no rifling marks.....

http://i18.photobucket.com/albums/b150/rinselman/guns/accelerator.jpg

isp2605
July 6, 2009, 04:00 PM
Of course, if you use THESE, there will be no rifling marks.....
There will be on the sabot. If used in a crime those will be left somewhere within the crime scene.

rondog
July 6, 2009, 04:03 PM
That bullet will travel a LOT farther than the sabot will.

1858rem
July 6, 2009, 04:03 PM
so how traceable are paper patched bullets?

isp2605
July 6, 2009, 04:10 PM
That bullet will travel a LOT farther than the sabot will.
That's right, but it's still all crime scene. Don't think just the point of impact is crime scene and that's the only place searches are conducted.

highorder
July 6, 2009, 04:11 PM
so how traceable are paper patched bullets?

Not very.

Look at how many unsolved murders there are from the 1890's... :neener:

Oyeboten
July 6, 2009, 04:12 PM
If Rifleing marks are present on what had been a Paper Patched Bullet...then a Forensic's Lab technition can desribe the Rifleing Marks...direction of twist...Bullet weight, composition if budget allows, size/diameter/length...as far as these are in the recovered Bullet, anyway.


For any recovered Bullet...I think it is exceedingly rare that any pronounement can be made as for what make or model Arm it came from.

Zoogster
July 6, 2009, 04:19 PM
One other thing I didn't see mentioned here is that many barrels are made by automated processes that create something almost exactly the same. Even when barrel A is different than barrel B, C or D, it may be a near match to barrel Y. When making thousands of automated barrels many of them will be very close. Through use, cleaning, polishing and other wear they will overlap many times throughout their lifespan.

This is more true on mass produced barrels that are very close than those made by smaller scale processes.
So your gun can ballistically match the gun of some thug someplace in the nation who just commited a crime. A year from now after firing several thousand shots, being polished and cleaned numerous times, they may have totally different marks and the same gun could overlap with the ballistic "print" of another similar model gun.

Prosecutors and "expert witnesses" many of whom make a living by being such "experts" will often discredit or deny that fact.


In reality the lie of the effectiveness is not as obvious or important because there is only a small percentage of guns being used in crimes. So even if a criminal's gun is giving a ballistic "fingerprint" that would match say 10 other guns in the nation, it is very unlikely those other 10 or their owners will even be a part of the investigation. Without those other 10 in the database nobody will ever know their guns were even matches as well.


If you were to take 10,000 glocks with polygonal rifling that is almost exactly the same from gun to gun, all in the same caliber, fire 10,000 rounds from each mixing them all together, then use a sample round to try to figure out which round came from which gun it would be very inaccurate.
A couple of the guns may have unique defects or marks that made it easier but even the ballistic print of the firearms themselves would have slowly changed during the course of the 10,000 rounds. Meaning round number 5 would not even match round number 5,000 from the same gun on many, never mind figuring out which gun it came from.

Now if you took some hand crafted barrel, with unique rifling, the uniqueness of the barrel would allow the fired round to be identified as being fired from the gun better.

Closed tests with several different models of guns with low numbers of rounds and virtually no wear, cleaning, polishing changing of parts etc are often used to demonstrate the capability of such technology. Quite misleading.


All of these facts are a big reason a ballistic database fails. The print changes through use, it overlaps other firearms during the course of the firearm's lifetime, continuing the change, receive new scratches, lose metal, have parts replaced etc.
If the database only includes firearms involved in crimes it is still not accurate beyond a reasonable doubt, but it does give good investigative conclusions.
If it includes all firearms it would be worthless, except for registering all gun owners.
Additionally it leads to "fishing". It means that if you have a .44 Magnum and a guy in your county was just killed with a .44 Magnum from a similar model firearm (or firearm using a similar barrel and breech) you may end up on a list of potential suspects even though you have no other connection to the case. This is even more true if the caliber or barrel, breech is more unique.
If you actually happen to have any connection or possible connection to that individual its certainly going to happen.
People may need to come inspect your gun on a regular basis just to conclude whether it was yours used or not.
The bigger the database the more likely yours will actually match other guns in the database. Since the print changes over time what other guns it matches will also change over time.

A big reason for the support of such systems by antis does not require the system to work. If all guns are part of such a database then all guns are registered. Period. Whether the system is a complete and utter failure you still would have all the guns in it and their owners registered. Something that allows better successful implementation of future gun control legislation.

eye5600
July 6, 2009, 04:38 PM
Additionally it leads to "fishing". It means that if you have a .44 Magnum and a guy in your county was just killed with a .44 Magnum from a similar model firearm (or firearm using a similar barrel and breech) you may end up on a list of potential suspects even though you have no other connection to the case.

This is already true of the car you drive. Do you worry about it?

Sam1911
July 6, 2009, 04:44 PM
This is already true of the car you drive. Do you worry about it?

No, but at the moment there is no national (and only a few state) registries which would give government agents the ability to look up who owns guns or which guns you own. So there is little chance of you getting a knock on the door from an officer saying, "Someone was just shot accross town with a .44. Our records indicate that you own a .44. Show it to us." Most of us prefer to keep it that way.

-Sam

Zoogster
July 6, 2009, 04:48 PM
This is already true of the car you drive. Do you worry about it?

It is not true of the car you drive in the same way. If your car is involved in a hit and run there is damage. If your car was not then hopefully you won't happen to have damage from something else.

A gun will be the same whether it was used or not.
Further the license plate of your car does not change over time like the "ballistic fingerprint" of a gun does. Your license plate will not match those of others, changing and matching new people throughout the life of the car.
The license plate of the car will not be different from mile 5,000 to mile 10,000 to mile 50,000, randomly changing as you use it.

Your car is also not demonized, and there is not large numbers of dedicated antis attempting to legislate against your car or your possession of your car.

Etc etc etc

CWL
July 6, 2009, 04:52 PM
other than simply matching calibers?

To further stir up the pot, it isn't simple to figure out caliber unless casings are found at a crime scene. For example, how can you tell if a bullet is a .38spl, .357 magnum or 9mm luger? They all make the same sized hole and pretty much look the same after being fired. Could even be a .380 ACP.

This is why medical examiners have to weigh each recovered bullet (and fragments) to try and determine original bullet weight.

highorder
July 6, 2009, 04:54 PM
Additionaly it leads to "fishing". It means that if you have a .44 Magnum and a guy in your county was just killed with a .44 Magnum from a similar model firearm (or firearm using a similar barrel and breech) you may end up on a list of potential suspects even though you have no other connection to the case. This is even more true if the caliber or barrel, breech is more unique.


I'm sure we all remember this:

http://thehighroad.org/showthread.php?t=386344

If you own this pistol, we want you to let us shoot it. If you don't let us, we will make you let us.

eye5600
July 6, 2009, 06:02 PM
It is not true of the car you drive in the same way. If your car is involved in a hit and run there is damage. If your car was not then hopefully you won't happen to have damage from something else.

I was thinking of a situation more like "the perp drove away in a red Camaro." There have been many cases where LE has run down all the owners of red Camaros (or whatever).

Of course, I agree about guns being demonized, while the danger of cars is taken for granted "because you need a car and you don't need a gun".

Sam1911
July 6, 2009, 06:17 PM
I was thinking of a situation more like "the perp drove away in a red Camaro." There have been many cases where LE has run down all the owners of red Camaros (or whatever).

Again, though, there is no physical way that the police can say, "let's go visit (uh, "run down?") all the owners of .44 Magnums." (In all but a very few jurisdictions) that information is not available to the government. Nor should it be.

-Sam

mgkdrgn
July 6, 2009, 07:37 PM
They match rifling marks by comparing two bullets - one found at the scene and a test round fired from a specific gun -- if they match then they know the same gun fired both bullets. I'm not aware of a rifling marks database that would let you "look up" what gun fired a given bullet. If there were such a database it'd be useless if the gun's owner ever changed barrels.

Or just ran a coat hanger through it a few times.

Firethorn
July 6, 2009, 08:21 PM
Cops are after criminals. Criminals are normally dumb. The smart ones generally aren't caught.

Cops can often catch a criminal just by asking questions, the criminal will eventually trip up over the lies. Heck, many just confess.

Assuming the average criminal will know to have a couple barrels and to catch his brass from any shootings would actually waste time for the cops - it's a quick check for them, no great loss if they're wrong, jackpot if they're right.

I haven't performed any barrel changes on my guns, I'm willing to be that most people on this board have mostly original barrels.

Still, you DO run into the fact that 1000x rounds out of 1000 new guns have more in common with each other than the first round and the thousandth round out of the same gun.

benEzra
July 6, 2009, 08:27 PM
Is it possible to link a bullet to a specific gun, other than simply matching calibers? For instance, from the rifling marks on the bullet?

I'm pretty sure it's not, but wanted to check.

Is there such a thing as a ballistics database in the US or certain states?
Bore markings on bullets are like tire tracks. Out of a small sample of cars, you can often match one to a given set of tracks, as long as not much time has elapsed for the tires to wear enough for the tracks to change. But tire tracks are NOT unique enough to create a national database of tread marks that would allow you to match a given track to a particular car out of 100 million, nor would such a database be useful since a car's tires wear over time and alter the pattern.

bigfatdave
July 8, 2009, 01:39 AM
Assuming the average criminal will know to have a couple barrels and to catch his brass from any shootings would actually waste time for the cops - it's a quick check for them, no great loss if they're wrong, jackpot if they're right.
In moments of free association and mind-wandering, I've often wondered why nobody scatters a handful or three of random range brass at their crime scene. To expand the concept that a .38spl/9mm luger/.380/.357 all spit a similar projectile, what if there was a nice collection of the wrong brass there, and the correct brass removed or still in the revolver.

I really shouldn't let my mind wander down those paths, but sometimes I just can't help it.

rondog
July 8, 2009, 03:11 AM
I also wonder what a really good scrubbing, de-leading, and de-copper treatment would do to ballistics results. Or a good scrubbing with steel wool, or even a few passes of emery paper on a stick.

Skillet
July 8, 2009, 11:58 PM
there are ways to get around this tracing.
paper wrapped bullets
accelerator rounds
and i'm sure of a few others.
just have to dig deeper.

inSight-NEO
July 9, 2009, 12:17 AM
There seems to be several ways of altering the "rifling" of a bore.

Hence, the whole "rifling mark" thing seems fairly weak to me, in terms of identification.

heron
July 9, 2009, 11:09 AM
Lead inside of a barrel can be matched to a specific bullet. The bullet lead can be matched with company records of chemical make up.This sounds like a long, thin stretch, to me.

Think about the market process involved. Bullet lead is not mined or alloyed by the cartridge makers; they buy it from raw-materials suppliers. Since the ideal alloy characteristics for a bullet will fall within some fairly narrow range, the raw-materials people probably have a "bullet lead" catalog item (maybe two or three kinds) that they sell to all the cartridge companies, in the form of very large wire coils. It may be that all the mass-produced ammo comes from only one or two raw-materials suppliers. Same for gilding metal, jacketing copper, and case brass.

Some foreign ammo makers may use different sources, but again, maybe not. And, just for fun, imagine what the receiving inspection process might be at the Wolf ammo plant, and how easy it might be to match a specimen to their records . . . and that's nothing compared to tracing the origin of something like, say a fifty year-old round fired from a Mosin.

There may be a few custom cartridge makers who are so fussy that they use a unique alloy, but those bullets are unlikely to be used in everyday crime.

I don't see any conclusive or useful information coming out of any such analysis.

daorhgih
July 9, 2009, 12:36 PM
...what my spent-bullets and fired-casings look like, in case any of the guns were stolen. Even the brass off a hull of each shot-gun. I have all of these in our safe-deposit box. The last two pistols I bought came with a spent-hull packed in the box. Easy to I.D. marks from firing-pin, breech-face, and rifling. CYOA.

Lou McGopher
July 9, 2009, 02:34 PM
Buckshot, slugs, sabot bullets, are pretty much untraceable via the rifling-groove method. Polygonal rifling is nearly untraceable.

http://www.firearmsid.com/

so how traceable are paper patched bullets?

As this guy. :D
http://i30.tinypic.com/r8fp7r.jpg

It was just a few nights ago, on CSI Miami, they took a bunch of tiny, tiny bullet fragments from some victim's body, and scanned them, and a computer put them all together like a jigsaw puzzle, and they got a match . .

Batman did this, too, except he fired the bullets into various bricks, then used the fragmentation pattern to reassemble the original bullet, in order to get a partial fingerprint match. Silly movie stuff.

Starting 2010, there will be many matching characteristics of both firearms and ammo. Micro Stamping of firearm serial numbers on firing pins and bolt/breech faces. lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.

Remember all the rave over facial recognition technology being deployed in airports and such? Turns out those expensive computers and cameras are easily defeated by hats and beards. Expect similar results from firearm tracking technology.

thorazine
July 9, 2009, 04:31 PM
How traceable are bullets?

Coat the bullet in some teflon.

It'll not pick up any markings from the barrel and the teflon gives it the strength to pass right through a M1 Abrams tank!!

expvideo
July 9, 2009, 08:19 PM
I'm a little concerned about the motives of the OP's question.

Also, I think a few of you are watching too much CSI. CSI is a great show and it demonstrates a lot of technology that does really exist, but it is also fiction. Most shooting investigations and even CSI teams have nowhere near the kind of resources to actually solve every murder like they do on the show. I was told by the chief of police for Mikilteo once that one of the worst things in recent history to happen to law enforcement was that show, because it set an unrealistic expectation of what capabilities and resources LEOs actually have, and now everyone expects their loved one's murder to be solved in an hour. The reality is that far more criminals escape than are ever caught, andmost departments have nowhere near the kind of resources and manpower to do what is done on CSI. I'm not trying to call LEOs ineffective, but expecting CSI level mystery solving out of real LEOs is unfair and unrealistic. It's a TV show, and you need to understand that it is fictional.

As for tracing bullets, as it has been said several times, it can be done to a degree, but it is very inaccurate compared to other forms of evidence like DNA or fingerprints. It is exactly like tire tracks as was mentioned above. If you have a dozen suspected cars and there hasn't been much wear to the tires, you'll probably have a match. If you were to take 200 new Glock 19s and try to figure out which bullet came from which gun, you might have some trouble. Now try doing that with 200,000,000 guns. Good luck.

The Lone Haranguer
July 9, 2009, 08:32 PM
It is possible to tell, to a degree, what kind of gun fired the bullet because many guns have unique rifling characteristics common to that make or model. The same also applies to firing pin/striker indentations in primers. But this does not prove which specific gun fired that bullet.

inSight-NEO
July 9, 2009, 11:31 PM
The last two pistols I bought came with a spent-hull packed in the box

As did mine...along with, Im sure, many others here as well. This really means nothing as these casings were reminants of an unaltered, newly fired weapon. Once any relative "alterations" have taken place, weapon specific info (other than caliber identification) goes out the window...to a degree.

In terms of rifling, Im inclined to think that simply swapping out barrels would do the trick if nothing else.

But, I personally have no need or desire to perform such alterations, so...

I can only hope that this thread is meant for posterity only.

CPerdue
July 10, 2009, 12:21 AM
Wanted for swap: Barrel for xyz. Will pay postage.

The chemical fingerprinting was debunked because of the size of the batches of lead. Yes, the shell in question matches others in a box from your house, but also thousands if not millions of others.

JMusic
July 10, 2009, 12:30 AM
I didn't read this thouroghly but bullets are about like finger prints. You can tell the caliber,bullet type and manufacture. If you have a gun to capre to then you looke for minute differences in the machining of the rifleing which is pretty consistant. The case and primer strike is another analysis.


Jim

trickshot
July 10, 2009, 10:46 AM
lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.
Is this really true? Please give some reference to back up this claim.

DJW
July 10, 2009, 10:50 AM
yours have your social security # imprinted............if you have such a # to begin with!

everallm
July 10, 2009, 11:21 AM
Starting 2010, there will be many matching characteristics of both firearms and ammo. Micro Stamping of firearm serial numbers on firing pins and bolt/breech faces. lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.

And the tags will all have RFID and GPS and will automatically capture, store and forward your DNA to the nearest UN black helicopter via the Vatican and NWO's Illuminati database which will track and shoot your kitten and puppy AND force you register your firearms on your tax form.

Did I miss anything..........

CPerdue
July 11, 2009, 12:19 AM
I did read some cool stuff about lifting prints from casings that had been wiped. There was no oil, no conventional finger print, left but they were able to detect a pattern of corrosion. Obviously it was invisible to the naked eye - took special chemistry and lighting to make it show.

209
July 11, 2009, 12:41 AM
Based on a task I was assigned a few years back, I assume there is some law in CT concerning police handguns and having a [fired] bullet and expended cartridge from each department handgun on file. There is a water tank maintained by one of the agencies for firearms testing so I took every handgun to the site and shot each one, recovered the brass and bullet, tagged each as needed and now I have a box containing all of that stuff.

What good it will do is questionable. All of the guns are now much older and in various stages of wear. Some have new firing pins, extractors and/or ejectors, and two even have new barrels.

But that just shows that laws are written that may address some nebulous "feel good" response to some perceived problem, but the reality is the law actually accomplishes nothing.

inSight-NEO
July 11, 2009, 01:54 AM
Starting 2010, there will be many matching characteristics of both firearms and ammo. Micro Stamping of firearm serial numbers on firing pins and bolt/breech faces. lead and other metals in bullets will soon have ID tags in them, the powders used will also have id tags. Shell cases will have NON wipable surfaces to capture finger prints.

Maybe plan on swapping various parts, deeply cleaning a weapon, using generic/easily available ammo (paid for in cash), destroy all unused ammo (of the same batch used for various deeds), retain all spent casings and wear gloves. Im sure Im missing something here...

Besides, all of this nonsense only matters if one is inclined to use a weapon for unlawful purposes. Outside of that...does it really matter?

Of course, what relatively intelligent criminal would use his/her own personal weapon for any dastardly deeds anyway?

Personally, I do not consider myself of the criminally minded persuasion, so this stuff does not matter much to me.

Phil Lee
July 11, 2009, 04:24 PM
Maryland's ballistic fingerprinting program is like New York's and both maintain a database of imaged shell casings. The intent of both programs is not to provide evidence for trial, but provide leads to detectives (go talk to this gun buyer becausse the registered shell casing from the database matched a casing recovered at a crime scene).

Both programs have failed, but for political reasons, have not been repealed. I believe Maryland is not processing shell casings anymore bit still requires their collection and the casings are being stored.

California Attorney General Lockyer evaluated ballistic fingerprinting and determined it could not be made to work with current technology. You may read more about that evaluation here (http://www.mcrkba.org/BallisticFingerprinting.html).

Ratshooter
July 11, 2009, 05:10 PM
I haven't read every post hear so forgive me if I repeat what has been said before. My uncle was a homicide cop on the Ft Worth PD and later an investigator in the DAs office. I quizzed him all the time about this very thing.

If the bullet is not too deformed it can be traced back to the gun that fired it with a high degree of certainty. There was a show on the Little Big Horn battle and they were able to recover cases from certain rifles and trace where it had been fired. IIRC they also did this with some of the bullets.

When JFK was shot part of identifying oswalds rifle and ammo was by using a Neutron activation test. This lets them compare the lead core to each batch of bullets and at least be able to say this bullet came from this run of ammo.

My uncle said it was very dificult to match bullets with the Lubaloy coating on them. They did not show the rifling very well.

There was 2 people that were driving around Ft Worth and shooting blacks with a shotgun. They were spotted by a prostitute who had hid in some bushes to take a leak. She got the plate number. After they were arrested my uncle was one of the investigators on the case.

The two shooters were from my town (Burleson) and I ran into my uncle at the local gun store. He was buying shotgun ammo from there and the local walmart so they could do the neutron activation test on the buckshot and prove the shooters bought the ammo. The ammo did come from walmart (where else) and was part of the case against the shooters.

Bullets are very traceable to the gun there were fired from. Altering the guns barrel so that they cannot be traced back is also very easy. It can be done in just a few minutes.

Phil Lee
July 11, 2009, 06:23 PM
Ratshooter
The FBI has discontinued Bullet Lead Analysis (BLA) (read about why from an FBI press release (http://www.fbi.gov/pressrel/pressrel07/bulletlead111707.htm)).

Ratshooter
July 11, 2009, 06:56 PM
Thanks Phil Lee I haven't read that before. At least they did for the right reason.

1858rem
July 11, 2009, 06:58 PM
i wonder if paper patching is for BP rifles only or if it can be done with modern smokeless cartridges, absolutely no leading and very cheap to reload

Odd Job
July 11, 2009, 07:08 PM
Some of you need to read up on class characteristics, subclass characteristics and individual characteristics.

Nice link here to get you going:

http://www.ojp.usdoj.gov/nij/training/firearms-training/module11/fir_m11_t04.htm

The AFTE Glossary defines identification as:

“Agreement of a combination of individual characteristics and all discernable class characteristics where the extent of agreement exceeds that which can occur in the comparison of toolmarks made by different tools and is consistent with the agreement demonstrated by toolmarks known to have been produced by the same tool.”

Ratshooter
July 11, 2009, 07:08 PM
1858 yes it can. Ross Seyfried wrote an article about doing this very thing. He used .308 bullets in a .318 bore Mauser rifle because .318 bullets aren't common.

I think the only place paper patching doesn't work well is in revolvers because of the bullet jump. Sabots don't work in revolvers either so i've read.

Rifle magazine has had at least two articles about doing this that I can think of.

1858rem
July 11, 2009, 07:12 PM
cool, i wonder what type of bullet mold it would take to paper patch for a .308 win.....the other id like to have is a 45-70for strictly lead boolits

Ratshooter
July 11, 2009, 07:28 PM
1858 I believe there are lots of bullet molds for paper patching the 45-70. Read some of Mike Venturinos articles on BPCR shooting or better yet he has a couple of books on the subject. There is also another series of books on this sold at rifle mag. Check thier website at riflemag.com look for PigIron & Lead.

The 308 is another matter. You might check with some of the custom mold makers like Hooch and Steve Garby. You might be able to patch a .284 (7mm) bullet to .308 but i'm thinking that might be a little thick on the paper. That would be a patch that is .024 thick total or .012 on the side. Then again it might be just fine.

daorhgih
July 16, 2009, 10:54 PM
THORAZINE: "Coat the bullet in some teflon." (is that dip or paint or spray??) "It'll not pick up any markings from the barrel..." (surely you jest!) "...and the teflon gives it the strength to pass right through a M1 Abrams tank!!" (Yup, you jest!) (Horatio Cain will prove otherwise.)
JMusic: "The case and primer strike is another analysis.."
In all of these cases one must remember that in forensics, 1+1=3 sometimes. Best bet: get a Defense attorney who is also a shooter, and KNOWS what "shadow of doubt" really means.
"Polygonal" rifling does mean "rifling." There is often a little more "scuffing" before the bullet begins to twist, but there IS "polygonal" rifling.
Ultimate answer: icepick, into the river.

Ditchtiger
July 16, 2009, 11:12 PM
I think it also possible to examine the rifling on the bullet and find out what model of gun it was fired from. Rifle verses pistol, twist rate, land and groove depth, type of rifling.

Oyeboten
July 16, 2009, 11:34 PM
Muzzle Loading Shotgun...( there'd be nothing to 'trace'...)

1858rem
July 16, 2009, 11:42 PM
better yet, regular cheap flea market shotgun with hand cast buckshot, no mfg. alloy to go on, if your far enough away, no powder residue either.

shotgun with lots of 30 cal slugs?

i think with the ML shotgun you have the distinct disadvantage there are far fewer shotguns fired off with either black powder or a substitute than smokeless and greatly increase the odds of being "traceable"

divemedic
July 17, 2009, 09:45 AM
The method of performing analysis on the alloys in bullets has been completely debunked as junk science. Read this article from 60 Minutes. (http://www.cbsnews.com/stories/2007/11/16/60minutes/main3512453.shtml)

Tobin spent months buying and testing bullets and consulting with manufacturers and found that bullets from the same batch weren't chemically uniform, that bullets from the same box didn’t always match, and that it was statistically possible for every bullet manufactured in the U.S. to have tens of millions of twins.

Also, there is:

Forensics on trial: chemical matching of bullets comes under fire (http://findarticles.com/p/articles/mi_m1200/is_13_165/ai_n6110026/)

Comparative Bullet Lead Analysis: A Case Study in Flawed Forensics (http://www.nacdl.org/public.nsf/0/eae800fde1b2e5c985256ef400675bd7?OpenDocument&Highlight=0,forensic,forensics,evidence)

sohcgt2
July 17, 2009, 11:05 AM
Quote:
http://www.ocshooters.com/Reports/cobis/ibis.pdf

This is a report on ballistic fingerprinting by MSP's Forensics Sciences Division. A great read (well the first few paragraphs, which is as far as I got through it).

Seems they consider it too flawed to proceed with and completely worthless as far as producing "hits."

They cite New York State's "sister program" which is costing $4 million A YEAR and has not yet produced A hit.

-Sam

The first few pages of this report prove what all of us have known all along. The legally purchased firearms are not the firearms being used in criminal actions.

LRaccuracy
July 17, 2009, 12:54 PM
Watch CSI on TV sometime. They can even match the alloy's the bullet is made out of.

divemedic
July 17, 2009, 01:49 PM
Watch CSI on TV sometime. They can even match the alloy's the bullet is made out of.

Read my last post. That method has been debunked. It is based upon junk science and was used to falsely convict hundreds, perhaps thousands, of innocent people.

1911Tuner
July 17, 2009, 05:05 PM
Coat the bullet in some teflon.

It'll not pick up any markings from the barrel and the teflon gives it the strength to pass right through a M1 Abrams tank!!

I hope that statement was an attempt at sarcasm.

The teflon coating on KTW ammunition is/was no more than a jacket, and was there to protect the rifling from the tungsten bullet core and to give it something to bite into...since it couldn't engrave the uber-hard alloy if the bullet were bore diameter, not...as many believe...to cause it to penetrate further and/or easier.

Upon penetrating hard targets, the teflon jacket peels off, and only the core penetrates. Even in softer stuff, the bullet sheds most or all of its teflon jacket.

And if you'd ever played with any KTW, and examined the shed jacket...you'd know that the rifling does indeed leave striations on it.

sohcgt2
July 17, 2009, 06:01 PM
Read my last post. That method has been debunked. It is based upon junk science and was used to falsely convict hundreds, perhaps thousands, of innocent people.

I doubt if anyone was ever convicted based on bullet metalurgy. Bullet metalurgy may have suggested cause to extend a warrant, but if it was key evidence then the prosecutor is most certainly... SUPER LAYWER...able to leap the bench in a single bound.

thorazine
July 17, 2009, 11:26 PM
I hope that statement was an attempt at sarcasm.

The teflon coating on KTW ammunition is/was no more than a jacket, and was there to protect the rifling from the tungsten bullet core and to give it something to bite into...since it couldn't engrave the uber-hard alloy if the bullet were bore diameter, not...as many believe...to cause it to penetrate further and/or easier.

I also heard spraying your bullets with some Crisco (the butter flavor all vegetable oil) reduces friction and chamber pressure. =)

-and-

Is a healthy alternative to fatty saturated fat oils.

divemedic
July 18, 2009, 10:57 AM
I doubt if anyone was ever convicted based on bullet metalurgy. Bullet metalurgy may have suggested cause to extend a warrant, but if it was key evidence then the prosecutor is most certainly... SUPER LAYWER...able to leap the bench in a single bound.

Read this 60 minutes story. (http://www.cbsnews.com/stories/2007/11/16/60minutes/main3512453.shtml) Lee Wayne Hunt tells Kroft he's been behind bars for over 22 years and 6 months, and maintains he's an innocent man. Hunt was convicted in 1986 of murdering two people in Fayetteville, N.C., based on the testimony of two questionable witnesses and what turned out to be erroneous ballistics testimony from the FBI lab.

For years, the FBI believed that lead in bullets had unique chemical signatures, and that by breaking them down and analyzing them, it was possible to match bullets, not only to a single batch of ammunition coming out of a factory, but to a single box of bullets. And that is what the FBI did in the case of Lee Wayne Hunt, tying a bullet fragment found where the murders took place to a box of bullets the prosecutors linked to Hunt.

Asked how important he thinks this was to his client's conviction, Rosen says, "I thought it was very important to our client's conviction. It was the single piece of physical evidence corroborating their story. And it came from, you know, it came from the mountaintop."

So 60 Minutes joined forces with The Washington Post to see if we could find some of the cases ourselves. Our producers and Post reporter John Solomon worked with The Innocence Project and a team of summer associates from the New York law firm Skadden, Arps, who conducted computer sweeps of court files.

We managed to identify 250 cases in which bullet lead testimony was a factor, and a dozen where it played a pivotal role in deciding the outcome. And that's after looking at only a small percentage of the total cases.

A half a dozen defendants, like a North Carolina pastor who was accused of killing his son-in-law, have already won their freedom or a new trial by appealing bullet lead testimony.

Others, like a Baltimore police sergeant convicted of murdering his girlfriend, and Lee Wayne Hunt, are still in jail.

sohcgt2
July 20, 2009, 07:22 AM
Lee Wayne Hunt tells Kroft he's been behind bars for over 22 years and 6 months, and maintains he's an innocent man. Hunt was convicted in 1986 of murdering two people in Fayetteville, N.C., based on the testimony of two questionable witnesses and what turned out to be erroneous ballistics testimony from the FBI lab.

Very few convicts admit guilt to outsiders. I had an aquaintance of over 10 years who maintained he was innocent after being released (served his full sentance). He recently killed his ex girlfriend and then himself. It is interesting that in this case you seem to trust the same "liberal media" that so many in this forum abhor. I guess whatever is convenient to the discussion.

divemedic
July 20, 2009, 08:14 AM
Very few convicts admit guilt to outsiders. I had an aquaintance of over 10 years who maintained he was innocent after being released (served his full sentance). He recently killed his ex girlfriend and then himself. It is interesting that in this case you seem to trust the same "liberal media" that so many in this forum abhor. I guess whatever is convenient to the discussion.

When it is backed up by reports from the people who worked in the FBI lab admitting that the science is flawed, yes. Even the ATF lab has admitted that the flawed testimony has put people in jail.

In the case that you so handily dismiss, the only physical evidence that links the convicted man to the crime was a bullet fragment that supposedly was traced not only to a specific LOT of bullets, but to a particular BOX of cartridges that were in the defendant's possession.

Also, read this actual scientific study (http://www.nacdl.org/public.nsf/0/eae800fde1b2e5c985256ef400675bd7?OpenDocument&Highlight=0,forensic,forensics,evidence).

Isn't it odd that I have offered proof, and all you offer is running your gator?

jackdanson
July 20, 2009, 10:55 AM
Well if the bullets have a bit of Phosphorus or other incendiary in the back of them they are immediately traceable to the source provided you are on the right angle.

LOL!

Also if you put a bullet on a piece of construction paper I'm sure it wouldn't be too hard to trace. The key would be to make sure it doesn't roll around.

Zoogster
July 20, 2009, 03:05 PM
I doubt if anyone was ever convicted based on bullet metalurgy.

The FBI used inexact science to convince juries for decades (as evidence primarily used in state cases as there is few federal homicide cases) that the exact lead alloy of a bullet could be traced and matched beyond a reasonable doubt.
The tecnique was Comparative Bullet Lead Analysis. Expert witnesses would testify in court that it was an exact and reliable science.
Essentialy it measures 7 other trace elements in lead to compare different batches of lead. However lead from many different batches matches regularly, and different size samples of one batch can accumulate different quantities of the trace elements. Essentialy it is so inexact that it was deemed no longer worth offering to Law Enforcement in 2004 because just the fact that it is used could taint cases.
This after being used since the 1960s to obtain convictions.
It can be used to show some correlation, but it can also match when there is no correlation, or not match when it should.


Watch CSI on TV sometime.
I hope that is a joke. CSI shows so many things that have ruined the potential jury pools of our nation.
It shows great exaggerations in accuracy of actual forensics, shows unrealistic results, and gives the impression of reliable results based on unscientific and unrealistic or impossible tests.
It regularly states or references laws and databases that don't exist (like all guns in Florida being registered), science that does not exist and also gives the expectation of absolute forensics in court.
It has as a result greatly undermined both prosecutions and defenses. Prosecutions because it gives an expectation of super accurate forensics for any crime. So guilty go free if such evidence is not what TV's expectations have given them (which is better than the reverse.)
Defenses because it gives greatly exaggerated accuracy and incorruptibility of forensics. Leading to convictions if even any forensic evidence is available, when it shouldn't. (So some innocent are proven guilty.)

In reality even inaccurate science often does result in guilty being convicted or innocent being set free when combined with the rest of the case, circumstantial evidence and motives. It is greatly exaggerated as evidence, effecting the overall outcome far more than it should. Flipping a coin to determine someone's fate would be accurate 50% of the time too, but certainly does not mean it should be used in trials.


In trials evidence is exaggerated by prosecutors on a regular basis. "Expert witnesses", some of whom have a career based on being an expert in a less than absolute science also exaggerate because it essentialy elevates thier value. While some merely parrot what others have taught them, without fully understanding the science behind it and its strong and weak points but knowing enough to perform basic analysis.

That is just when the evidence itself is honestly collected. A bias of those collecting the evidence can also greatly determine the result, even without corruption.
Having once lived in an area that had a very corrupt police force I am fully aware how forensics and other things are abused to result in convictions. While the word of a lying officer may not always result in a conviction if challenged, falsified forensics ususaly will.
Many of the corrupt were actualy otherwise good guys, tired of seeing bad guys get away with crimes or remain on the street. So they were merely insuring arrests and convictions of people they thought were guilty by planting evidence, moving a little hair or DNA here or there, planting drugs or weapons taken from others etc. Many times those they created false evidence to convict really were bad guys they wanted off the street, some with long previous rap sheets. They were cleaning up the streets, and were quite effective through corrupt practices. Of course they also would take down innocent or less guilty ( of minor or lesser offenses) people if they ever fell into the crosshairs as well. They were essentialy insuring those arrested were denied real due process because the scales were always tipped in favor of conviction with false evidence. Such LEO were bad cops, but certainly wouldn't have seen themselves that way as they cleaned up neighborhoods by denying criminals (or those they believed were criminals) thier rights while giving an official appearance of honest due process.

Oyeboten
July 20, 2009, 04:52 PM
Basically...'tracing' any Bullet, when it can be done at all, amounts to very little more than IF one has the suspect Gun on hand, to fire test rounds into Water or Cotton, and, compare those to the Bullet in question.


And that's about it.


If the suspect Gun is not on hand, you can pretty well forget any honest conlusions of specific provenance being made on the basis of the Bullet only, as far as any real particulars of the Arm it had come out of, other than they can weigh and measure and desribe technically, the Bullet they have and compare it to known Ammunition manufacturers or Calibres...rate of twist of Rifling...and guess from there.

This alone will not per-se be able to distinguish the Arm that fired it...let alone all the endless other examples where they will not be able to say conclusively, even the Calibre designaion, let alone make of Arm the Bullet came from.


Handloads of course are even harder to pronounce conclusions about.

sohcgt2
July 20, 2009, 06:21 PM
Isn't it odd that I have offered proof, and all you offer is running your gator?

I just said that I don't believe that anyone has ever been convicted based on that evidence (bullet metalurgy). Did it help support a case? Yes, probably. Was it the only evidence linking the accused to the crime? I don't think so. If you can get the court transcript and show the prosecution only showed bullet metalurgy as evidence I will concede your point, otherwise I will continue to believe that other evidence of guilt was presented.

In the case that you so handily dismiss, the only physical evidence that links the convicted man to the crime was a bullet fragment that supposedly was traced not only to a specific LOT of bullets, but to a particular BOX of cartridges that were in the defendant's possession.

So you maintain he had no relationship with the co-defendant? Have you ever fired a weapon that belonged to a friend? I have. Babies are innocent Lee Wayne Hunt was not.

Oyeboten
July 20, 2009, 07:41 PM
The 'Warren Report' had a lot of yamering at one point, about having supposedly hired the National Atomic Laboratory or somesuch, to analyse and compare metalurgy of Bullet Fragments and Bullets, attribued to what was supposedly Oswald's Mauser, errrr, then, 'Mannlicher-Carcano'...in support of the accusations against him...

sonier
July 21, 2009, 07:48 PM
so if you ever were accused, just rebarrel the rifle, and keep your brass;)

inSight-NEO
July 22, 2009, 04:03 AM
All of this talk about "traceable' bullets....First off, I can think of a handful of ways to defeat this (most are already known). Regardless, if I were to commit any type of gun-related crime, I would simply destroy the weapon and any ammo associated with it. Not to mention, I would opt for using a revolver (no ejected casings). Keep in mind, this would probably be a stolen weapon as well.

But, Im not a criminal... nor am I CSI. So, Im only throwing out hypotheticals here. Frankly, I have never given this sort of stuff much thought.

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