SOMERVILLE, N.J. (AP) A weapons expert will be allowed to testify for the defense in the Jayson Williams manslaughter trial about how he induced misfires in the same model of shotgun that the retired NBA star was holding when it fired as he snapped it shut, killing a chauffeur.

Over prosecution objections, state Superior Court Judge Edward M. Coleman said Thursday the jury could determine what weight to give experiments performed by the expert, Richard Ernest.

During a hearing without the jury present, Ernest said testing showed that the Browning Citori 12-gauge shotgun malfunctioned in 70 of 100 attempts when a wood chip was placed in a specific portion of the firing mechanism.

The defense maintains that wood chips found in Williams' weapon could have caused an accidental firing.

First Assistant Hunterdon County Prosecutor Steven C. Lember said the test was not relevant, noting Ernest said it could not be replicated outside a laboratory and that Ernest never found a wood chip in that location in Williams gun.

The hearing was watched by Will Griffin, a lawyer for Browning, which is based in Mountain Green, Utah. Afterward, he said Ernest often testifies against gun makers and that ``there's no basis in fact for any of the opinions that he's attempting to offer.''

A prosecution expert who tested Williams' gun has testified that the weapon operated properly, firing only when the trigger was pressed and the safety was off.

Ernest began testifying to the jury about noon.

The defense began its case Wednesday, using its first witness, noted forensic pathologist Dr. Michael Baden, to raise questions about the location of one eyewitness and whether Williams attempted to put his shotgun in the hands of a dying man.

``Eyewitness testimony can sometimes be inaccurate at times of high tension,'' said Baden, medical examiner for New York State Police and former medical examiner for the city of New York.

The shooting happened as Williams gave a tour of his Alexandria Township mansion to friends and members of the Harlem Globetrotters in the early hours of Feb. 14, 2002.

In addition to aggravated manslaughter, Williams, 36, is charged with altering evidence and persuading his houseguests to lie by saying they were downstairs when Christofi shot himself.

The eight charges carry penalties of up to 55 years in prison. The least of the charges carries a penalty of up to 18 months in prison, but would likely result in probation.

Williams had gone with some friends to see a Harlem Globetrotters game in Bethlehem, Pa. Christofi had driven four Globetrotters from the game to a restaurant near the Williams estate for dinner with Williams and most of the group. They then went to the mansion in Alexandria Township.

Williams from the New Jersey Nets in 2000 after a decade in the NBA, unable to overcome a broken leg suffered a year earlier in a collision with a teammate. He was suspended from his job as an NBA analyst for NBC after the shooting.