Ballistic fingerprints (Forensic Science)
The examination of ballistic fingerprints is part of the field of internal ballistics, which is the study of events that begin when the firing pin of a rifle or handgun strikes the cartridge and end when the bullet exits the barrel. Ballistic fingerprinting is not a new science. In June, 1900, Dr. Albert Llewellyn Hall published an article titled “The Missile and the Weapon” in the Buffalo Medical Journal, in which he presented the first analysis of bullet marks imparted by rifling in a gun barrel.
The interior of the barrel of a rifle or handgun has raised and lowered spirals, called rifling, that impart spin to the bullets as they are fired, making them more aerodynamically stable. As a bullet is pushed down a gun’s barrel by the gas that is generated by burning gunpowder, it is etched with fine lines, or striations, from the rifling. Under microscopic examination, these striations look something like the parallel lines of a universal product code. In addition, “skid marks” may be left on a bullet in the short period after it leaves the firing chamber and before it is fully engaged by the rifling.
The striations common to all guns of a particular model are known as class characteristics. Individual characteristics are the striations unique to a particular gun; these result from tiny imperfections in the rifling process and in the rifling tools used as well as from the wear and tear caused by the particular usage...
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Further Reading (Forensic Science)
Burnett, Sterling, and David B. Kopel. Ballistic Imaging: Not Ready for Prime Time. Dallas: National Center for Policy Analysis, 2003.
Heard, Brian J. Handbook of Firearms and Ballistics: Examining and Interpreting Forensic Evidence. New York: John Wiley & Sons, 1997.
Warlow, Tom. Firearms, the Law, and Forensic Ballistics. 2d ed. Boca Raton, Fla.: CRC Press, 2005.
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Ballistic Fingerprints (World of Forensic Science)
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 statesaryland and New Yorkad 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,
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.
SEE ALSO Ballistics; Bomb damage, forensic assessment; Crime scene investigation; Firearms; Gunshot residue.