By DON THOMPSON, Associated Press Writer

SACRAMENTO, California - Two related California studies to be released this week conclude it is currently impractical to catalog the ballistic "fingerprints" of every firearm in the state.

Recording every firearm made and sold in the nation's most populous state could be overwhelming, according to an internal California Department of Justice (news - web sites) report obtained last fall by The Associated Press.

Supporters of a proposed nationwide database fear the report, combined with an independent review of it, will further undermine congressional support for a national firearms database inspired by last fall's Washington area sniper attacks. The reports, along with a federal rebuttal, are to be submitted to state lawmakers.

Gun control supporters want the state to lead the way by passing legislation requiring manufacturers to provide a bullet "fingerprint" for every gun made and sold in California, which sells and produces more guns than any other state. Currently, Maryland and New York require ballistics be kept only on handguns.

California's initial study found the number of potential computer matches in the state "will be so large as to be impractical," that "a large proportion" of weapons couldn't be recorded, and that each gun's markings change with routine use and can be easily altered.

State Attorney General Bill Lockyer delayed the release of the state report while he submitted it for reviews by the federal Bureau of Alcohol, Tobacco and Firearms, and by independent ballistics expert Jan De Kinder of Belgium.

The ATF disputed much of the California report, saying that with systems being developed by the ATF and FBI (news - web sites), "large-scale ballistic comparison goes from an impossibility to a valuable investigative tool."

De Kinder, of Belgium's National Institute for Forensic Science, supported the state study and disputed the ATF's rebuttal.

Such databases hold promise, De Kinder concluded, but not without improvements in the current technology. The system tested was ineffective in a third to two-thirds of test firings, and "the situation worsens as the number of firearms in the database is increased," he found.

His review will be included as an appendix in a report Lockyer will send to state lawmakers, said spokeswoman Hallye Jordan.

Lockyer is expected to conclude that a statewide database for large-scale ballistics comparisons is not currently practical and to recommend more research and development.

Wayne LaPierre, executive vice president of the National Rifle Association, said the studies illustrate that "this needs a lot more study or a lot of money will be wasted."

Gun control advocates said De Kinder's report shows such databases hold promise even if they're not ready yet.

"We think the system has tremendous potential. It clearly needs more support and development," said Luis Tolley, Western director of the Brady Center to Prevent Gun Violence. "It's similar to where we were 10 years ago with DNA."

Ballistics comparisons are widely used to match bullets to specific firearms, or to link bullets found at different crime scenes to the same weapon. Long before they had suspects in custody last fall in the Washington-area sniper attacks, investigators used such comparisons to conclude that bullets recovered in separate shootings came from a single rifle.