Firearm microstamping
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Firearm microstamping, ballistic imprinting and ballistic engraving are all names given to a technology that engraves a unique identifier onto a firearm's cartridge under the pressure of firing. This information is intended to be used to connect fired cases from a crime scene with a particular gun, and allow a trace subsequently to be run on empty cartridges found at the scene of a crime. A new technology, ballistic imprinting has not been implemented by any firearms manufacturers, but has been subject to intense political debate by various groups.
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[edit] The technology
Due to the extreme pressures present in the chamber of a firearm during firing (see internal ballistics) the cartridge case is effectively forged into the chamber, and will pick up any markings, large or small, present in the chamber. This fact has long been used in the field of forensic ballistics, where marks from tooling that remain in the chamber or on the bolt face are often used to associate a cartridge case with the firearm that fired it. This method is generally called ballistic fingerprinting.
The newer ballistic imprinting technology, patented by Todd Lizotte and presently owned by ID Dynamics, uses microscopic engraving on the firearm to record information about the firearm; generally make, model, and serial number, and serve to identify a firearm uniquely. In the method most often proposed, the identifying marks are engraved on the face of the firing pin which then stamps the primer both as the firing pin impacts the primer to ignite it, and as the chamber pressure pushes the primer back into the firing pin. By marking the replaceable primer rather than the reusable case, each time a case is reloaded the new primer supplies a fresh writing surface upon which to accept the identifying engraving.
If one or more fired cases from a ballistic imprinting firearm is/are left at a crime scene, it should be possible to obtain the unique firearm ID from the case(s), and trace the gun from the manufacturer, to the distributor, to the dealer, and to at least the first retail customer. In the case that a FFL dealer is used to transfer the used gun from one state to another state, it could even be possible to trace a fired case found at a crime scene to additional owners of the gun, at least until such time the gun is sold in a state where no FFL transfer agent is required. Still, at this point the paper trail becomes less reliable, since private firearms sales are not regulated in most states. Once a transfer has occurred between private individuals in jurisdictions where this is legal, prior owners of a firearm may not be able to provide any significant information on subsequent private buyers or sellers. Supporters of legislation requiring ballstic imprinting technology hope that the paper trail will be sufficient to allow gathering evidence in some crimes, and also allow better tracking of firearms from manufacturer to any criminal, perhaps leading to arrest(s) of straw purchasers.
[edit] Controversy
In general, groups that support gun control legislation favor requiring ballistic imprinting on all new firearms, while groups opposed to gun control oppose any legal requirement for ballistic imprinting technology. Since the technology is unproven, there are no reliable statistics to substantiate how useful the process might really be to law enforcement.
Claims made by proponents of the technology include:
- Ability to match fired cartridge cases from a crime scene to at least the first registered owner of the firearm
- Ability to track illegal trade in guns
- Low cost of implementation; the technology owner claims US$0.25 to US$0.50 per firearm in royalties
- High reliability; the "nearly as hard as a diamond" firing pin provides long service life
Claims made by the opponents of the technology include:
- High costs that must be passed on to customers, increasing cost of firearms, for testing the efficacy of the technique,
- Legal costs that must be passed on to customers, increasing cost of firearms, for any cases in which the technique causes a failure to ignite primers on cartridges, perhaps leaving a law enforcement officer with a defective gun that fails to fire when most needed, potentially exposing gun manufacturers to class-action law suits for selling defective merchandise
- Poor reliability, as a firing pin is prone to wear, and any micro-stamping of the firing pin could introduce microscopic crystalline cracks in the firing pin, thereby causing an early failure in the firing pin to occur
- Ease of defeating the imprinting, by defacing or replacing the firing pin, or simply shooting a large number of rounds through a firearm. Firing pins are normally a replaceable item, requiring replacement if a gun is used to fire many rounds of ammunition.
- Increasing the likelihood of snapping the end off a firing pin when dry-fired, due to excessive work-hardening of the surface of the firing pin from the initial imprinting of identifying information.
[edit] The technique in testing
George G. Krivosta, of the Suffolk County Crime Laboratory in New York, did some research on the firearm microstamping technology offered by NanoTag. In his research, using tagged firing pins in a .22 Long Rifle rifle and a .45 ACP pistol, he found that very few firing pin strikes actually resulted in legible marks, as it was very common for the firing pin to bounce on impact and strike the case more than once, with successive strikes landing slightly off of the original position and obscuring the original strike impression. Out of the first 100 rounds fired using an 8 character alphanumeric code, 54 provided satisfactory markings, while the remaining 46 had at least one illegible character. Smaller print, encoding the make, model, and serial number for a total of 45 characters, resulting in far less clear markings which were difficult to decipher even under ideal circumstances. Subsequent testing was done only with the 8 character coded pin.
The remaining testing was done using 10 different M1911 pistols of various make and age, with the test firing pin being moved from pistol to pistol as groups were fired with standard military type .45 ACP ball ammunition. After each 100 rounds was fired, the pin was removed from the pistol, examined, and placed in the next pistol. After 1000 rounds were fired, the markings on the pin were still readable, though the markings were beginning to soften under the repeated impacts of firing.
The last test involved an intentional defacement of the markings on the pin. The pin was removed (a simple operation taking a few seconds on the M1911), chucked in a power drill, spun, and held against a knife sharpening stone for about 10 seconds. Examination of the pin showed some marking remaining at the very center of the firing pin, so the pin was wiped against the stone three times by hand, which removed all traces of the engraving. The tip was of the pin was then rounded to remove any sharp edges, placed back in the pistol, and fired with 10 rounds. No malfunctions were observed.
[edit] Associated legal issues
In addition to the attacks on the technology itself is a question involving other legal issues. It is illegal in most jurisdictions to remove the serial number, or even to possess a firearm with the serial number removed. The firing pin is a commonly-replaced part, due to breakage, wear, or a desire for increased performance provided by a lower mass pin (see accurize), or to increase safety from inertial slam-fires if the gun is accidentally dropped on its muzzle. With a ballistic fingerprinting law in place, replacement of a properly-marked firing pin would remove the manufacturer's identifying marks on the firearm, introducing the gun owner to legal action for defacing identification marks on the firearm. Sales of used firearms would also be impacted, as a cautious buyer would need to require verification of the imprinting marks, which would require the firing of a case, and an inspection of the fired case with a microscope, or of an inspection of the firing pin point, to read the marks and verify they match the firearm, since it would be possible to swap firing pins in same-model firearms. Simply firing the gun numerous times could also cause the micro-stamping marking on the firing pin to be eroded away with use, which could also become a crime if identifying marks were worn off the firing pin. A high volume shooter, firing multiple tens of thousands of rounds per year could find his gun becoming illegal just from use having eroded away any micro-stamping marks. Additionally, with $0.25 worth of sandpaper, it would be possible for criminals to deface intentionally the surface of the firing pin in a matter of seconds to remove any identifying marks, which would require a microscope to verify had been done. All of these issues pose serious problems which would have to be overcome were the technique to be required by law.
It would also be possible for someone planning a criminal act to obtain fired casings with markings from a shooting range, for planting at the scene of a planned crime, erroneously linking unrelated gun owners to the crime scene to introduce doubt in any subsequent jury trial. As not all bullets recovered from crime scenes are intact, which can prevent matching striations, this twist would introduce considerable confusion in processing and prosecuting criminal cases at the expense of innocent individuals.
[edit] Legal jurisdictions considering microstamping
The California Assembly bill AB 352 would require all firearms sold in California to be capable of stamping fired ammunition, and also allow for the Attorney General to require all ammunition to be serialized. The bill was defeated by a narrow margin in a 38-34 vote on August 30, 2006.
[edit] References
- Contra Costa Times article on current California microstamping bill (AB 352)
- Gun Owners of California report on AB 352
- John Lott article on Maryland ballistic fingerprinting
- NanoTagTM Markings from Another Perspective, By George G. Kirvosta, Suffolk County Crime Laboratory, Hauppage, New York, Published in AFTE Journal, Volume 38 Number 1, Winter 2006
