Last year, special prosecutors dismissed an involuntary manslaughter charge against Baldwin, saying they were informed the gun might have been modified before the shooting and malfunctioned.
Defence attorneys for Alec Baldwin are seeking to scuttle an involuntary manslaughter trial against the actor-producer in the fatal shooting of a cinematographer during rehearsal for the Western movie Rust.
Baldwin has pleaded not guilty to the involuntary manslaughter charge, which carries a maximum sentence of 18 months in prison.
During the trial, an FBI expert testified the gun was fully functional with safety features when it arrived at an FBI laboratory.