Chances are, you've seen them on your local newscast - the haul from the latest "gun buyback." The TV camera pans a table filled with tagged firearms, as a police officer announces the final tally: dozens, if not hundreds, of "dangerous" weapons taken "off the street," never to menace the community again.

But before you breathe that sigh of relief, ask yourself: How much of a difference do these programs make? Are crimes being prevented because Washington has set aside $15 million to supplement local buyback programs? Or is it all just a PR stunt, designed to convince nervous soccer moms that something is being done to protect their kids?

Unfortunately, the answer is mostly the latter: The gun buybacks provide good photo-ops but do little to improve public safety.

It's understandable that many people think otherwise, since local officials are always declaring them a success. But when you look at who's selling weapons and what they're turning in-not to mention the impact on crime rates-you realize that buybacks aren't making our streets any safer.

Start with the sellers. Check the line snaking around the block at the average buyback, and who do you find? Not the young punks who use guns to hold up the local 7-11 or "hit" rival gang members. What you will find, notes Boston University law professor Randy Barnett, are mostly "law-abiding folks who probably have no use for the gun." Surveys taken during various buybacks show most of the people turning in guns are middle-aged and elderly-those least likely to be potential shooters.

Also consider the weapons being turned in. To make a real dent in crime, buybacks would have to attract lots of pistols, such as the 9-mm semi-automatic pistol used in an April shooting at the National Zoo in Washington, D.C. After all, pistols are used in 65 percent of all handgun homicides, according to the Medical College of Wisconsin's Firearm Injury Center. But only 32 percent of the handguns bought through buybacks are such weapons.

Do buybacks reduce crime? The Police Executive Research Forum, a Washington-based group of big-city police chiefs, evaluated buybacks in Boston, Seattle, St. Louis and other major cities and found they had no effect. In Seattle, researchers checked coroner's records and hospital admissions data for six months following a buyback and said it hadn't reduced gun violence at all. Small wonder that University of Pennsylvania professor Lawrence Sherman told Congress that buybacks are "a sellout to doing what works to make news, not public safety."

Garen Wintemute, head of the Violence Prevention Research Program at the University of California-Davis, calls buybacks "a triumph of wishful thinking." Even if they attracted the kind of weapon most likely to be used in a crime, they would still have a negligible impact, he told the Chicago Tribune. Estimates of the number of privately owned guns in the United States range from 200 million to 350 million, with at least 4 million more added annually. Buybacks are taking-at most-3 million out of circulation each year, Wintemute notes, meaning the total number is actually increasing.

Those who favor such programs usually just deny the evidence. White House officials say the programs work, all right, but in ways that are hard to measure. Any gun the police buy is another gun off the street, they claim. They're right-but that fact is mostly irrelevant.

Before more taxpayer money is used to entice yet another rusty revolver out of the old shoebox under the bed, we need proof that buybacks reduce crime. Until then, its proponents are just shooting blanks.

Edwin J. Feulner, Ph.D. is president of The Heritage Foundation, a Washington-based public policy research institute.