"Ballistic fingerprinting" is the most innovative part of a wide-ranging package of gun control proposals made by New York Gov. George E. Pataki. No ballistic fingerprinting system exists anywhere, although the U.S. Bureau of Alcohol, Tobacco and Firearms is working to create one.

The system Pataki proposes for New York would work like this:

• Manufacturers would be required to test-fire new handguns before they are sold in New York.

• The spent bullet and shell casing would be sent to the state police, who would record the unique pattern of nicks and scratches on them.

• Ideally, when investigators find a bullet or shell casing at a crime scene, they would feed its characteristics into the computer, which would search for any possible match in a state computer database.

But Robert T. Delfay, president of the National Shooting Sports Foundation, a gun industry group, said a gun's markings change slightly each time a gun is fired, and after enough rounds are fired making a match would be impossible. A gun's markings can also be altered by roughly inserting a cleaning rod into the barrel, he said.

State officials say that even after extensive firing the marks are consistent enough to supply valuable leads. And criminal justice experts say most criminals won't make the effort to cover their tracks.

Source: Richard Perez-Pena, "Gun Proposal May Do Little to Curb Crime," New York Times, March 27, 2000.