Forensics Casebook: Ammo Mixes for Tracing


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Luchryman
August 12, 2004, 05:51 PM
In The Forensic Casebook , by N.E. Genge, the author has a discussion of tracing bulllets and casings found at a crime scene. He then goes on to discuss "Gun Shot Residue." One thing that bothered me was this:

Many manufacturers deliberately include metal additives in known proportions, so tracking individual batches of ammunition becomes a possibility.

And that's all he says on the subject. It doesn't seem clear what he means, so maybe someone here can bring some light on the subject. Do ammo companies actually include trace materials, or is he just refering to different powder compositions? Also, what's with the "batches" thing? Minor, accidental varations in production, or additions specifically for matching a bullet to a specific run of ammo?

Is this a case of poor wording or misunderstanding, or do ammo companies actually make traceable ammo?

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biere
August 12, 2004, 06:31 PM
The technique also can be used to identify manufacturing byproducts, impurities and dyes in explosives that may point to the country or manufacturing plant where they originated, Yinon said

http://www.globaltechnoscan.com/12thJuly-18thJuly/tracking_terrorists.htm

The above is a quote from the linked article and the article was found running a google search using the phrase "tracking explosives" without the weird double marks on each end of it.

Overall, if you lack a tin foil hat it would most likely be able to show stuff up from normal contaminants found in maybe arizona vs virginia. I prefer the tin foil hat when dye is mentioned since that means they can do each batch different and track down a time line pretty fast.

Also note for those who don't care to read the article this is a new way of examining residue and what not, so I don't know how exact this article can compare to today's techniques.

I am no expert, don't work in the field or anything else. I do recall reading in some articles where explosives were used that the residue led them to so and so company who made it.

Figured I should edit this to say yeah I know I posted about explosives while the new member was asking about smokeless powder. I figure the two would have similar techniques in creation and research, but maybe I am wrong.

SDC
August 12, 2004, 07:09 PM
I wouldn't say that it's deliberate, but the specific concentration of various elements in ammo components HAS been used as corroborating evidence in the past. The trouble is, since they make ammunition in lots of thousands of rounds, and there's always the possibility of "contamination" between those lots, it can't be considered as anything close to "proof" that the bullet that was found in the victim came from the box of ammo found in the suspect's possession. The FBI recently had its wrist slapped for trying to make such a case, and I think if it's mentioned in the future, it'll only be after they've already proven their case by another method.

possenti
August 12, 2004, 08:13 PM
Is this the same thing as "tagents" that our Concress-critters tried to foist on ammunition and propellent manufacturers after OKC?

What I've read about this technique, it's unreliable and the NRA claimed that it could also make for some dangerous loads for reloaders.

Of course, the NRA was accused of "protecting terrorists" by the media because they opposed this legislation.

Jim K
August 12, 2004, 08:24 PM
Several years ago, there were proposals for legislation requiring "taggants" to be put in powder used in ammunition so residue could be traced. Opposition, primarily from the NRA, was based on potential damage to guns, the immense cost of inserting the taggants, and on the record keeping required. To have been effective, each round, or at least each box, of ammunition would have had to have a separate taggant identity and a tracking system that would provide a legal chain of evidence.

Congress rejected the idea both for propellants and true explosives, but there have been reports that some companies have used it in dynamite and other explosives anyway. The taggants are not "metal additives", but tiny microcoded "chips". When one of the idea's proponents was questioned about possible damage to guns, he replied that "we never considered that as a problem, and people should not be allowed to have guns anyway." Pretty well shows that the goal was not simply to catch criminals.

The idea is not dead, though, and sometimes is raised by the anti-gunners as "a means of stopping terrorists that was shot down by the right-wing gun lobby" or words to that effect. Look for it in the various pro-Kerry "independent" campaigns.

Jim

jason10mm
August 13, 2004, 12:03 PM
This is a total smokescreen put up by those WAy too ignorant about anything even remotely firearms or forensics related.

First off, modern "gunshot residue tests" don't test for gunpowder in the first place. They actually test for metal deposits from THE PRIMER. Levels of lead, antimony, and barium can all be detected by various means, including neutron activation, flameless atomic absorption spectrometry (FAAS) and scanning electron microscope-energy dispersive x-ray spectrometry (SEM-EDX). of these, on the latter 2 are in real use in the US. Various primer companies use different amounts or combinations of the metals listed above in their primers, allowing SOME analysis as to the manufacturer of the cartridge (or at least a source for the primer). FAAS is not a "YES" or "NO" test, it is open to a LOT of individual interpretation.

There are other "environmentally friendly" primers out there with strontium, potassium, calcium and silicon, and titanium and zinc combinations. These can be tested for as well. Be aware that there are everal environmental sources for these elements, including the lead bullet, the jacket, or dirt.

SEM-EDX can visualize individual particles, so could theoretically be used to id a manufacturer specific particle, but that still begs the question about whether or not it is a useful thing to know. What if the guy used mixed ammo? Or a rifle/shotgun? No residue there, or conflicting results at best. Besides, it is meaningless unless you want to track every cartridge sold in the US, which would pretty much end shooting as a sport. OH WAIT, that's the point!!!!!

I got most of this info from Dr. Vincent Di Maio's "Gunshot Wounds" book, vol 2, pp 328-335

Jim K
August 13, 2004, 05:49 PM
All of the above is true, but I have to admit that the taggant idea would have made life easier for the evidence folks. Tests did show the taggants were not destroyed and could be found in the residue, even in wounds. Had the system been implemented as planned, the police could say that the shot was fired from a round sold in Winchester box #12345, and that box would be traced to Joe's Gun Shop, where Joe's records would show it was sold to Pete Doe. So the cops arrest Pete, and that is it. No fancy analysis or expensive machines required, only a chip reader.

Of course, the box of ammo cost $525.95, but that is a small detail, as people shouldn't have guns anyway. Oh, and by the way, one version of the proposal would have exempted police and military ammunition, so if a cop was involved, his rounds could not be traced. It's called protecting the cops, good and bad, at all costs.

Jim

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