Countering Branch Davidian survivors' offer of a gunfire-and-videotape simulation, the government proposed its own test yesterday to determine whether federal agents fired gunshots on the final day of the 1993 siege.

The question of government gunfire is a key facet of the wrongful-death lawsuit filed against the government by survivors and relatives of those who died during the standoff--and has become a focus for the special counsel reinvestigating the deaths.

Federal officials say that no shots were fired by government forces on April 19, 1993, when the 51-day siege near Waco, Tex., ended in a deadly fire. Davidian leader David Koresh and some 80 followers perished during the blaze, some from the fire, others from gunshot wounds. The government says the Davidians died by their own hand.

The plaintiffs, however, contend that information collected by the FBI itself--aerial infrared surveillance footage--offers proof that federal agents fired into the Davidians' compound on the final day.

Arguing that rapid bursts of light on the infrared tapes represent machine-gun fire, they proposed to stage a demonstration in which guns like those carried by federal agents and the Davidians would be fired while an infrared camera similar to the FBI's would record the action from a plane.

The Justice Department rejected the proposal, offering to do a private test for the special counsel investigating Waco.

Special counsel John Danforth this month asked the federal judge presiding over the wrongful-death case to supervise an impartial demonstration. U.S. District Judge Walter Smith Jr. asked the government, plaintiffs and Danforth to agree on how an infrared demonstration would be conducted.

The Justice Department, in a 10-page filing with the court yesterday, said that the full-scale simulation proposed by the plaintiffs could not replicate the sun, wind, temperature, heat source and soil moisture conditions present that day and "would produce more confusion than clarity."

Instead, they proposed a test that would determine whether gunfire can be detected by the Forward Looking Infrared (FLIR) technology deployed at Waco at specified ranges. And they suggested that the testing protocol agreed to by the judge and the other parties examine other "possible sources for the flashes that appear on the FBI FLIR tape."

The plaintiffs' lead counsel rejected the government's offer as a "shell game. . . . They claim that a more reliable test than using the same camera and the same airplane is using two different pieces of equipment? That's the silliest thing that I've ever heard of," said Houston lawyer Michael Caddell.

The government says details of the infrared camera and FBI Nightstalker airplane, which are "often used in foreign counterintelligence investigations," must remain classified. And, the Justice lawyers said, the FLIR camera used at Waco has been "modified and upgraded significantly" since 1993.