Ballistic Fingerprinting Brief

Ballistic Fingerprinting

Fired bullets and shell casings have markings that can be traced to the firearm in limited circumstances. These so called “ballistic fingerprints” are not unchangeable properties of the firearm. California has found (reference: Feasibility of a California Ballistics Identification System, Attn. Gen. Bill Lockyer, Calif. Dept. of Justice, Jan. 2003 referenced here as CAAGR) that "ballistic fingerprints" of shell casings varied so greatly in a laboratory trial that 38% of trial guns firing the same ammunition couldn't match the second shell casing fired from a new handgun with the first casing fired and when the second casing was from a different type of ammunition 62% could not be matched to the same gun (see CAAGR Attachment D, page 3 of 22 -- no longer available at the AG web site, but we saved it and Attachment A, Attachment B and Attachment C also). The performance of "ballistic fingerprinting" in this trial was so poor that Attorney General Bill Lockyer stated in a press release that "our analysis concludes that today's technology is not yet adequate to handle the volume associated with adding all new guns to the database and still provide useful information for investigators" (reference his press release Attorney General Lockyer Releases Report on Ballistics "Fingerprinting" Database, January 29, 2003, 03-013).

The California attorney general has stated that “ballistic fingerprinting” technology is not likely to be effective and he recommended in January 2003 that California not adopt such a program. In the original posting by California, this report contained a number of interesting appendicies (and the California attorney general's press release describing the system failure) which are no longer to be found on California web sites but can still be found on the Internet Archive site. In particular, Attachment D is an interesting report by an independent Dutch ballistics expert commenting on the California test and the effectiveness of the IBIS system for the intended purpose and explaining why IBIS technology will not be useful. Appendices A through F are also available via the Internet Archive.

Without first studying the problem and the capability of the technology, Maryland and New York adopted laws in 2000 requiring new handguns sold in retail to have a shell casing submitted to the state for ballistic fingerprinting with the hope that shell casings recovered at the crime scene can be linked to the criminal responsible. Unlike Maryland and New York, California decided to study the problem before passing a law.

Not one crime has been solved via collected shell casing programs of New York and Maryland. The millions of dollars spent on these programs could have been better spent on additional police, prosecutors, or prison facilities instead.

“Ballistic fingerprinting” performance is low because of technology and affordability issues which are likely to persist for the foreseeable future.

For “ballistic fingerprinting” of shell casings to identify the criminal user of a firearm, the criminal must fire the firearm and leave a shell casing to be recovered at the crime scene. This shell casing must then be linked by comparison to the gun in the legal retail sales data base, and the retailed record must link to the user either directly or through investigations.

“Ballistic fingerprinting” programs will rarely aid investigation of shooting crimes, will not serve to deter criminal use of guns and will not be cost effective since:

1) The technology doesn't work even in ideal conditions! California reached that conclusion (see CAAGR), by test firing a total of 2,000 rounds from 790 different pistols of the same model. When the shell casings used with a particular gun came from the same manufacturer, computer matching failed 38 percent of the time. When the casings came from different manufacturers, the failure rate rose to 62 percent. Normal wear and tear was a minimum in these cases since the test rounds were fired immediately after the round used to create the “ballistic fingerprint. Normal wear of the mechanical parts making the marks used in "ballistic fingerprinting" will increase real world failure.” Nor was this failure limited to the computer matching tool – 16% of the shell cases could not be matched even by an expert examiner with more than 30 years experience and approximately 42% of the remaining cases had unfavorable markings which might have prevented matching by the expert.

2) Computer matching of ballistic fingerprints has a high false match rate requiring trained ballistic examiners to make the final determination from a number of candidates. False matching by the computer increases with the size of the database of ballistic fingerprints and increases the work for human examiners. That means more examiners will need to be trained and employed and that is a cost ignored by proponents of the technology. The California Attorney General concluded that current “ballistic fingerprint” technology is too costly and ineffective for comprehensive application on a database of legally sold firearms.

3) Criminals frequently alter firearm serial numbers to prevent tracing, and could alter the ballistic fingerprint of a gun in a few minutes (3 minutes according to CAAGR, Appendix F).

4) Criminals using revolvers do not normally leave behind shell casings at crime scenes. It is wasteful to collect such information from revolvers as Maryland does (we note that the number one gun used in crime in is a Smith & Wesson .38 revolver so this technology will be relatively ineffective against the gun most frequently used by criminals).

5) 500,000 guns are estimated to be stolen annually (see Comprehensive Firearms Tracing: Strategic and Investigative Uses of New Data on Firearms Markets, Philip Cook & Anthony Braga, University of Arizona Law Review 43, no. 2 (Summer 2001) and by definition these guns are available to the criminal market. Such guns cannot be traced back to the users by ballistic fingerprinting. Approximately 40% of guns used by criminals were stolen or bought on the illegal street market (especially criminal recidivists are more inclined to use this source -- see Firearm Use by Offenders, Bureau of Justice Statistics Special Report, November 2001, NCJ 189369).

6) Crimes are frequently committed with illegal firearms, that is, the firearms are unregistered, stolen, or modified in some way (see The Licensing and Registration Status of Firearms Used in Homicide, Jenny Mouzos, Public Policy Series, No. 151, Aust. Inst. of Criminology, Canberra). Hawaii, which has had registration and licensing of guns for several decades, has spent hundreds of thousands of man-hours administering these laws. This massive effort has not produced a single case with police claiming that licensing and registration were instrumental in identifying a criminal.

7) Maryland, despite its ballistic fingerprinting of handguns, has continued to have the highest rate of robbery of any state (see MarylandCrime7.doc), so suggesting that criminals are deterred by “ballistic fingerprinting” is to hope against evidence.

8) Even proven crime fighting technologies lack money. For example, a recent Rand report notes the problem with “The results of DNA testing on violent crimes is backlogged, causing delays in the freeing of suspects or prosecution. The delay in processing toxicology tests is hindering benefactors from settling insurance claims and estates of loved ones that have died. Without toxicology reports, coroners cannot issue death certificates required by insurance companies.” See Challenges and Choices for Crime-Fighting Technology: Federal Support of State and Local Law Enforcement, William Schwabe, Lois M. Davis, Brian A. Jackson, Rand, MR 1349.
Only irrational ideologues could justify spending money on "ballistic fingerprinting" that solves no crimes while leaving rape kits unprocessed that could convict criminals. That is the situation in Maryland. (see the ABC report which said "Hundreds of thousands of rape evidence kits sit unprocessed on dusty shelves in police storage rooms around the country simply because police say they can't afford the cost of processing them, which is on average no more than $500 per kit.")

In the case of ballistic fingerprinting of newly sold guns, the cost will always be very high compared to the value of the results because: a)only about 1% of new guns will ever be used in crimes, b) only a small fraction of guns used in crimes can be traced to the criminal user even when the gun is recovered at the crime scene (nearly 90% of guns used in crime change hands at least once since their initial purchase at a licensed dealer before being used in a crime according to Bureau of Alcohol, Tobacco, and Firearms, Crime Gun Trace Reports National Report (1999), November 2000), c) ballistic fingerprinting technology is unreliable as California has shown in part because the fingerprints of guns do change with normal use of the gun or can be altered easily by a criminal user.

Updated by Phil Lee on 8/22/07. Contact pflee at wdn dot com (sorry for being obscure, but web mail address scavenge programs make this practice necessary).