Firearm microstamping

Firearm microstamping, ballistic imprinting and ballistic engraving are all names given to a controversial technology that has been developed with the alleged goal of aiding in ballistics identification; it involves the use of laser technology to engrave a microscopic marking onto the tip of the firing pin and onto the breech face of a firearm. When the firearm is fired, these etchings are transferred to the primer by the firing pin and to the cartridge case by the breech face, using the pressure created when a round is fired. After the spent cartridges are ejected, these microscopic markings are imprinted on the cartridges, which can then be recovered by police and examined by forensic ballistics experts to obtain information to be used to trace the firearm through its life to, supposedly, the purveyor of the crime.

This technology was to be required in California starting in 2010, however, it is on hold and law enforcement is specifically exempt. On May 17, 2013, California Attorney General Kamala Harris announced that micro-stamping had cleared all technological and patenting hurdles (orly?) and would be required on newly sold semiautomatics, effective immediately.

Yep, that's about the size of it.

The Technology

A .40 S&W cartridge case. The primer has been imprinted by the firing pin.

The technology was developed in the 1990s by Todd Lizotte and Orest Ohar for the computer technology industry and has the intent to "Provide[s] Make, Model, and Tracking Number At The Crime Scene". It is currently patented by Mr. Lizotte and owned by ID Dynamics. Due to the high pressures present in the chamber of a firearm during firing (see internal ballistics), the cartridge case is effectively forged into the chamber, and picks 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. Firearm microstamping technology additionally engraves the make, model, and serial number on the cartridge, and serves to identify a firearm uniquely. The identifying marks are engraved on the face of the firing pin which stamps the primer as the firing pin impacts the primer to ignite it, and as the chamber pressure pushes the cartridge against the breech face, onto the head of the cartridge as well. By marking both the replaceable primer and the reusable case, each time a case is reloaded, a new primer supplies a fresh writing surface upon which to accept the identifying engraving, although for factory-fresh cartridges, the same information will be available in legible form on both the primer and on the head of the cartridge case. Imprinting both the primer and the head of the cartridge increases the tamper-proofing, relative to just imprinting the primer, as the firing pin can easily be reworked or replaced if only it does the marking of the spent cartridge.

The goal of microstamping is that if one or more fired cases from a ballistic imprinting firearm is/are left at a crime scene, it should generally 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 between private individuals 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 ballistic 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.

Controversies

In general, groups that support gun control legislation generally favor requiring ballistic imprinting on all new firearms, while groups supportive of gun rights and the Second Amendment generally oppose any legal requirement for ballistic imprinting technology. Since the technology is unproven with large scale implementation, there are no reliable statistics to substantiate how useful the process might really be to law enforcement or that it would in any way hurt these same efforts.

Claims made by proponents of the technology include:

• Microstamping enables law enforcement to match fired cartridge cases from a crime scene to at least the last registered owner of the firearm.
• Microstamping would allow law enforcement to track illegal trade in guns.
• Low cost of implementation; the technology owner claims as low as US$0.50 per firearm or as high as US $8.50, depending on the volume of the manufacturer.
• High reliability; the "nearly as hard as a diamond" firing pin provides long service life.

Claims made by the opponents of the technology include:

• Stamped casing can only be traced to the last registered owner, not to the person who used the gun when the casings were stamped. In the case of a stolen gun, as is the case for most firearms used in crime, the stamped case would not lead to the criminal.
• Unscrupulous individuals could collect discarded brass from a firing range and salt crime scenes with microstamped cases, thereby providing false evidence against innocent people and increasing the workload for investigators.
• High costs for testing the efficacy of the technique must be passed on to customers, increasing the cost of firearms for those who obtain them legally.
• Micostamping is easily defeated. Diamond coated files are inexpensive and will remove microstamping. Firing pins are normally replaceable and can be changed with simple tools or without tools. Firing a large number of rounds will wear down the microstamp. Marked components such as slides, barrels, firing pins and ejectors are all easily and commonly replaced items.
• Microstamping is an immature, sole source technology, and has not been subjected to sufficient independent testing. Transfer of microstamped marks to the cases is less reliable than proponents claim.
• Microstamping would be irrelevant/non-applicable for implementation of revolvers as these types of weapons do not eject shell cases necessarily.
• Ejected casings can be easily collected and removed from a crime scene.

Specific to California, opponents say:

• Firearms sold to law-enforcement are exempt. Problems could arise if a police officer's firearm is used in a crime or stolen, and the fact that a firearm is "unsafe" if not provided with stamping technology exposes the police to liability.
• Guns manufactured before an effective date are exempt and the bill does not extend to guns outside of California. There's no possibility that this bill would ever cover enough guns to provide the investigative advantage claimed for it by the proponents.
• Failures of the microstamping parts of a firearms makes it "unsafe" under the California law, which then becomes illegal to sell, give or lend under existing law.

The Technique in Testing

Manufacturer Testing

Studies conducted by the developers of the technology, including a 2,500 round stress test resulted in a legible transfer rate of 100% (note that the service life of a typical military or police handgun is an order of magnitude higher). In addition, the technology includes stamps on the breech face and residual markings that extend the functional length of the firing pin. Manufacturers claim that even when the microstamp is removed, and this requires rudimentary technical knowledge of the stamp and firearms and the use of power tools or diamond sandpaper, the breech face and the residual marks are still transferred and identifiable.

Suffolk County Crime Laboratory

George G. Krivosta, of the Suffolk County Crime Laboratory in New York, investigated the firearm microstamping technology offered by NanoTag. His basic thesis for this experiment states: "The science of Forensic Firearm and Toolmark Examination relies on the use of highly trained and skilled individuals to identify & compare accidental markings left on expended ammunition components. To circumvent the need for these individuals, it has long been suggested to rely on manufacturer-generated unique characteristics that would be transferred onto the expended components." The owner of microstamping technology claims "markings will be readily identifiable at the crime scene ... with 100% reliability, with little or no training of the analyst needed...".

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.

The study found that the ratio of unsatisfactory markings, where at least one of the 8 characters was not readable under a microscope, was 46%. It also questioned the validity of a number of alternative the marking techniques, designed to go on other areas of the firearm:

• Headstamps could interfere with case head markings other than on the firing pin
• Low pressure rimfire cartridges are unlikely to pick up breechface markings
• Recoil operated designs using the Browning tilting barrel (the majority of recoil operated handguns made) would cause shearing marks on the case head markings, as would gas operated designs (rare in handguns, but common in rifles) using a rotating bolt.
• Some marking locations shown in the NanoTag marketing literature showed marks on the extractor and ejector in areas that never come into contact with the ammunition.
• Chamber markings would need to be placed deep in the chamber, and would be subject to shearing under extraction

A side by side comparison done by NanoMark in response to Krivosta's findings is available for review. [1]

University of California, Davis

The UC Davis study was performed by graduate student Michael Beddow under the supervision of David Howitt, a professor of chemical engineering and materials science, and chair of the Graduate Group in Forensic Science at the university. The test involved engraving firing pins from six brands of semiautomatic handguns, two semiautomatic rifles and a shotgun. The firing pins were engraved with an alphanumeric code on the face of the firing pin, a pattern of dots or gears around the pin, and a radial bar code on the side of the pin, a process recommended by ID Dynamics to make the markings more robust.

The wear testing was done with six Smith & Wesson .40 S&W pistols used by California Highway Patrol cadets in training, who fired approximately 2,500 rounds through each pistol. The alphanumeric codes on the firing pin faces were still legible, but showed signs of wear, while the dot and bar codes were "hammered flat", according to Beddow.

Other firearms tested inlucded .22 Long Rifle and .380 ACP handguns in addition to the rifles and shotgun, and a wide range of results were attained. In general, the alphanumeric and gear codes transferred well, but the barcodes showed significant visual degradation, though due to lack of information on reading the codes, mechanical reading was not attempted.

Beddow found that the codes on face of the pin could easily be removed with household tools. The estimated cost of engraving the pins was US$8 for each pin the first year, and US$2 per pin from that point on.

A side by side comparison done by NanoMark in response to the UC Davis Study is available for review.

Controversy

The studies by Krivosta and UC Davis have been challenged by proponents of the technology. The UC Davis study was not peer reviewed and used firearms far older than those that would have the technology equipped (see below for UC Davis rebuttal). In addition, the Chancellor of UC Davis wrote a letter of apology for "mis-impressions" given by the study that was not peer reviewed and was prematurely released, which violated UC Davis policies. The UC Davis study has been submitted for peer review, which is pending, and a corrected press release is available. Krivosta's study was published in the American Firearms and Toolmark Examiner's Journal, a peer reviewed publication.

Update on UC Davis study

The study by UC Davis was peer reviewed by three independent researchers, updated, and was re-released in May 2008. The revised report concluded "At the present time, therefore, because its forensic potential has yet been fully assessed, a mandate for the implementation of this technology in all semiautomatic handguns sold in the state of California is counter-indicated. Further testing, analysis, and evaluation are required." The study also called into study the pricing estimates given by the manufacturer and the usefulness of the serial number information in solving gang shootings.

In rebuttal to the claims that the study used outdated firearms, the firearms in the study were chosen to provide a broad range of calibers and action types. Some of the firearms, such as the Smith & Wesson 4006 and Sig Sauer P-229 used by the California Highway Patrol, are current issue and were purchased new; others included the Colt M1911 design, which is still in production after nearly a century, the Ruger MKI, the Mossberg 500, and the Colt AR-15, all very common, established designs, still in production with minimal changes over the lifetime of the design.

Associated Legal Issues

The issue of liability for the gun owner if the firing pin is replaced or if the chamber marking is removed may constitute violating federal and/or state statutes that impose strict penalties for defacing the serial numbers of firearms. However, in an amendment proposed to the bill passed in California AB 1471, this issue is addressed, at least for the state level:

"The microscopic array of characters required by this section shall not be considered the name of the maker, model, manufacturer's number, or other mark of identification, including any distinguishing number or mark assigned by the Department of Justice[of California], within the meaning of Sections 12090 and 12094."

The microstamp is therefore not considered the serial number in California law, for the intents and purposes of the California penal code. It is still unclear if such penalties may be prosecuted at the federal level, as there is no concrete definition of a "manufacturer's serial number."

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. Likewise, range brass, acquired at a range and reloaded, would still be marked with confusing markings on the head of the cartridge case, even after reloading. As not all bullets recovered from crime scenes are intact, which can prevent matching striations, these twists would introduce considerable confusion in processing and prosecuting criminal cases at the expense of innocent individuals.

Legal Jurisdictions

States Using Microstamping

Microstamping legislation was passed in California AB 1471 and signed into law on October 14, 2007, but specifically exempts law enforcement.

States Considering Microstamping

Similar legislation is under consideration in Connecticut, New York, Rhode Island, Massachusetts, Maryland, Wisconsin, and Illinois.

Legislation at the Federal Level

Federal bill H.R.5266, the National Crime Gun Identification Act of 2008, was written by House Rep. Xavier Becerra (D-CA). Senator Edward Kennedy (MA) introduced an identical companion bill in the Senate.

US National Research Council Study

The United States National Research Council released a report on March 5, 2008 that concluded that a national database of ballistic markings is unworkable and that there is not enough scientific evidence that, "every gun leaves microscopic marks on bullets and cartridge cases that are unique to that weapon and remain the same over repeated firings".

Additional Resources

• United States National Research Council report "Ballistic Imaging"
• Gun Owners of California report on AB 352
• John Lott article on Maryland ballistic fingerprinting
• UC Davis Forensic Science report on firearms microstamping, corrected revision here
• See a presentation on Capitol Hill about the technology by the developer and some others: Part 1, Part 2, Part 3, Part 4, Part 5, Part 6
• Coalition to Stop Gun Violence (CSGV) Microstamping Page