Embedded microembossing technology marks cartridge casings as they are ejected from the firearm.

Ballistic fingerprinting has its critics. Used for years, it involves analyzing the unique markings of fired bullets and empty shell casings and then matching them to specific firearms. Proponents say ballistic studies help law officers match guns with crime-scene evidence. Critics, on the other hand, claim the technique is just a way to register and eventually confiscate all lawfully owned handguns. They also say ballistic markings can be easily altered, essentially making the "fingerprints" useless.

One company aims to change that with an alternative tagging technology said to be proof positive. NanoVia LP, Londonderry, N.H. (www.nanovia.com), has developed a microembossing technique that stamps each cartridge casing as bullets fire. The microscopic code can be made up of encrypted symbols, bar codes, or simple alphanumeric codes, such as the make, model, and tracking number. Manufacturers can access the code to find out a firearm's serial number and purchasing history. The company says these identifiers, called NanoTag Ballistic ID Tags, would immediately lead investigators to a specific gun without requiring the extra manpower and expense associated with trying to match "scratches and dings" that can be easily altered. The technique uses imaging equipment found in local, state, and federal forensics labs.

NanoVia is working with the State of California Department of Justice to test various code configurations and to see where the embossing surfaces should sit within the firearms for forensic value and repeatability.