The federal government plans to join the increasingly popular gun buyback movement with a $15 million program aimed at reducing the number of firearms that are available in the nation's public housing projects, administration officials said yesterday.

The program, to be announced by President Clinton at a White House ceremony today, will give local police departments up to $500,000 each to purchase guns in and around public housing projects for a "suggested price" of $50 apiece. Except for stolen guns, which will be returned to their owners, all firearms purchased under the program will be destroyed, officials said.

The administration described the initiative as the "largest gun buyback program in American history," although it is modeled on similar local programs, including one in the District that netted 2,306 guns in two days last month.

Housing and Urban Development Secretary Andrew M. Cuomo said that while gun control legislation that the administration is pushing in Congress is needed to reduce the number of new guns that are sold, "we also have to reduce the number of guns that are out there already. We have about 200 million guns out there. We have to reduce that number, and the buyback is a way to do that."

A HUD official estimated that at a cost of $50 per gun, police could buy 280,000 guns with the money that will be available under the program. He said the administration hopes the first grants to local police departments will be made by mid-November.

Under the program, $10 million will be distributed to police departments that apply for grants of up to $500,000 each. The money will be funneled through local public housing authorities after they reach agreement with the local police on the details of the buyback plan. In addition, another $4 million will be made available to the housing authorities in grants of up to $200,000 each to extend their buyback efforts or to undertake related projects to reduce violence.

The remaining $1 million of the $15 million program will go to an as yet unnamed national law enforcement organization to study the effectiveness of this and other buyback programs, officials said. They said the $15 million will come from HUD's Drug Elimination Grant Program, which provides money to combat drug use and crime in and around public housing developments.

A HUD official said that under the gun buyback program, local police will be encouraged to find alternatives to cash payments for guns, such as offering vouchers for food, toys or other items in exchange for weapons.

"We've talked to housing authorities that are very much in favor of doing this," the official said. "I expect there's going to be immense interest in this. The housing authorities see gun violence as a major problem."

According to HUD, the nation has 3,191 local housing authorities with a total of 1.3 million housing units and 3.25 million residents.