Make and model identifiable from casing?
I'm reading the "Lincoln Lawyer" and here describing how the police can determine what make and model a murder weapon was simply by the unique marks made on the ejected casing.
I can understand matching rifling between slug and barrel, and Glock's rifling, but being able to match casing markings to manufacturer and model?
I can understand matching rifling between slug and barrel, and Glock's rifling, but being able to match casing markings to manufacturer and model?
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That is supposedly true, that it is easier to match the weapon from a fired casing, than the fired projectile, mostly because the projectile gets so beat up. There are micro machine marks that are stamped into the casing, that can be common with certain makes and models of fire arms.
This was a big issue in NY, as we had a program for 10 years or so, called COBUS, where for new handguns being sold, there had to be a fired casing from that hand gun, included with it from the manufacturer. That casing was sent to the NY State Police, by the dealer, when the handgun was sold. That program has bit the dust in the last 2 years, as it cost about 11 millon dollars a year to run it, and it had not solved one crime...mainly because criminals do not pertain to laws.
Since then, there has been enacted the NY S.A.F.E. act, which changed a bunch of definitions(next definition change will most likely be that any firearm cabable of firing more than one round, with out manually reloading it with another round, be deemed an "ASSAULT WEAPON"), so the anti gun group of King Andrew Cuomo, and his Majesty, Mr. Michael Bloomberg, can head toward their agenda of confiscation.
Everyone should take heed in that last paragraph, as the deal with NY, was just a warm up for the POTUS campaign. If we are not careful, the whole nation, will end up with the problem, NY, has now.
Best
EDIT 1
quote:Some guns leave distinctive marks, the HK Mp5 fluted chamber is an obvious example, the cases always look different then the ones fired by a Glock on the same line.
Glock also has a rectangular firing pin intentation, which is different from many other's.
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Just another Writer That does not have a CLUE.Guns do not have D.N.A.
When I read a book that makes a statement like this. I Throw it in the trash where it belongs.
The only area that touches the shell casing is the Magazine the chamber the breach face of the slide or recoil plate in a revolver & the tip of the firing pin. Some pistols will smear the imprint in the primer But darn sure are not the same for each different make and different model, but exactly the same for each pistol within that model. [:(]
EDIT Ok I am not trying to be argumentative but does anyone really believe every police dept keep files on exactly what marks each and every model of firearm produces. I still think if you have a fired case and you have a firearm one may be able to tell if that gun fired that case but to have a fired case and state in a court of law that it was fired in a Colt combat commander is B.S. More differences between two colt combat commanders then one commander and one government model.0 -
Charlie's question was about identifying a make & model, not matching a fired case to a specific gun.
Some guns, like Glocks, mutilate the fired case in a predictable way that would allow you to pin it down to a relatively small number of models. There are a few other guns that produce unique markings on fired cases.
So, maybe the best answer is, "it depends".
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quote:Originally posted by WearyTraveler
I'm reading the "Lincoln Lawyer" and here describing how the police can determine what make and model a murder weapon was simply by the unique marks made on the ejected casing.This can be true, but it's a small percentage of the time.
Rather than markings left on the case from the chamber itself, it's a matter of certain firearm designs having a unique combination of extractor design/size, ejector design/size, firing pin design/protrusion.0 -
quote:Originally posted by WearyTraveler
I'm reading the "Lincoln Lawyer" and here describing how the police can determine what make and model a murder weapon was simply by the unique marks made on the ejected casing.
I can understand matching rifling between slug and barrel, and Glock's rifling, but being able to match casing markings to manufacturer and model?
Bluntly, most of the time, this is NOT true.
IE, in the overwhelming majority of cases, its NOT possible to just pick up a spent case off the floor and come up with a definitive brand/type of gun it was shot from.
Its probably possible in CERTAIN cases, when specific models of gun leave characteristic combinations of chamber and extractor marks on a spent case. EG, certain guns have unique extractors, chambers, etc.
Realistically, the best way to make a match is match a particular gun to a particular case AFTER you have the gun in question! IE you fire test cases from the gun, and compare marks to your case in evidence, to see if they match.
quote:Originally posted by Mobuck
Keep in mind that 100 years after the Little Bighorn battle, forensic investigators were able to track certain firearms from one end of the battle field to the other by examining the fired cases.
All they're doing in that example matching spent cases to EACH OTHER. (IE seeing that the spent cases came from the exact same weapon). That was also done with weapons made in a era when there were FAR fewer types of weapons in each caliber.
In fact, in that era in at least some cases caliber and weapons were basically synonymous. . .certain makes of guns would only take one type of cartridge, and in turn that cartridge could only be used in that make of gun. Also, there was quite a bit less sophistication in manufacturing of the weapons. . .these guns weren't turned out by fancy CNC machines by the millions with effectively identical parts requiring absolutely zero fitting. Less parts tolerance = more characteristic individual marks put on a cartridge by a particular gun.
Here's an example. If you were a police detective in 1909, if you saw a spent 9mm parabellum cartridge lying on the ground, you could be 100% sure it was shot a Luger pistol. (And more likely than not you spoke German!).
By 2009, that same 9mm luger cartridge could have been fired through quite literally several HUNDRED different makes and models of pistol. Except under fairly unusual circumstances, definitively tying that cartridge to a particular make of pistol sight unseen would be impossible. The only way to do it would be to compare to particular weapon to see if it matched.0 -
Keep in mind that 100 years after the Little Bighorn battle, forensic investigators were able to track certain firearms from one end of the battle field to the other by examining the fired cases. 0 -
That is because the fired cases had the same markings from the individual gun that fired it as it moved about the battlefield, those don't vary much during a brief encounter like Little Bighorn. That is easy to do with microscopic examination of the cases.
Over years or lots of hard use those markings will change as the action/chamber metal wears, etc.
Some guns leave distinctive marks, the HK Mp5 fluted chamber is an obvious example, the cases always look different then the ones fired by a Glock on the same line. But I can't recall ever hearing or using any "database" with millions of fired cases from millions of different firearms in a memory bank somewhere where a case can be plugged in and the actual gun info spit out like the fantasy world of CSI etc....fiction is fiction, and that book seems to be a bit of fiction.0 -
I would guess that "lincoln lawyer" is a work of fiction. As such, it takes literary license with it's "facts" it uses to push a story along. So called "ballistic fingerprinting" is more like ballistic tire tracks. A very good lab tech that is properly trained might be able to tell what type of gun due to the marks-H&K's are an example, or some guns that were done in multiple calibers that have a square rather than round firing pin, or maybe some that have more than one extractor or the extractor and ejector placement is unique. But in the real world it would be like someone looking at a tire track and saying the vehicle that made it has to be a certain car. There is just no reality to the statement.
The whole thing was cooked up to get a way to register guns. The marks change over time. The "evidence" can sometimes be inconclusive. Remember the rifle used to kill Martin Luther King? The ballistic evidence is inconclusive if it was the gun that fired the fatal shot, while the shooter said it was the gun he used. Sometimes there just isn't any evidence left.
The ONLY way that you can match a gun to a certain casing is to check against that gun itself, not against a database of all the guns in an area. That is how they were able to find some of the Custer guns. By first checking the serial numbers against the known database of Trapdoors that were in the supply line at the time of the battle, and finding some of those few guns they were able to narrow them down due to the limited number of cases found.0 -
Yes - it's certainly a work of fiction. Thank you all for the information! 0 -
On the NCIS show Abby was able to tell that a fired case came from a 25 MM Tokarev.[:D] I would sure hate to be hit by a bullet from that pistol. That was the second time on that same episode they had called it a 25 MM. 0
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