Ballistic Fingerprints

A ballistic fingerprint is the unique pattern of markings left by a specific firearm on ammunition it has discharged. The technique has been used in forensic science to match a bullet obtained from a victim to a particular gun. This can help determine the cause of death as well as being instrumental in criminal prosecutions.

In 1997, the National Integrated Ballistics Identification Network, established by the Federal Bureau of Investigation and the Bureau of Alcohol, Tobacco, and Firearms, made 8,800 ballistic fingerprint matches, which resulted in the linking of 17,600 crimes. As of 2000, two states—Maryland and New York—had passed laws requiring the ballistic fingerprinting of weapons. Upon selling a firearm, a dealer was required to provide the state with a spent round from the gun, so as to establish a permanent record of the gun's ballistic fingerprint. Other states followed suit.

Despite this, the use of ballistic fingerprinting as a tool of forensics is controversial. On the one hand, many law-enforcement officials insist that ballistic fingerprints are as useful as ordinary fingerprints in linking a round of ammunition to a specific gun. Police used ballistic fingerprints, in part, to link the shootings of numerous people in the Washington, D.C., area during the fall of 2002 to the accused "Beltway snipers," John Muhammad and John Lee Malvo. The case brought ballistic fingerprinting to national attention.

On the other hand, many advocates of gun-owners' rights maintain that these fingerprints change so much over time that they are largely useless as a means of matching a spent round to a firearm.

Criminologist Daniel W. Webster, director of the Center for Gun Policy and Research at Johns Hopkins University in Baltimore, is an advocate of ballistic fingerprints as a tool of forensics. In Comprehensive Ballistic Fingerprinting of New Guns, Webster cited research suggesting that although ballistic fingerprints change over time, these changes do not prevent authorities from establishing a match between a firearm and a spent round.

However, technical factors may limit the current use of ballistic fingerprinting in forensic science. An independent study contracted by the California Department of Justice and conducted by the National Institute for Forensic Science reported in early 2003 that ballistic fingerprinting was impractical. Testing revealed that the computer software used to match the discharge pattern on a bullet with a specific firearm was too inaccurate to be reliable.