Former US Marine Corps Drill Instructor R. Lee Ermey was not originally hired to play Gunnery Sgt. Hartman but as a consultant for the Marine Corps boot camp portion of the film. He performed a demonstration on videotape in which he yelled obscene insults and abuse for 15 minutes without stopping, repeating himself or even flinching - despite being continuously pelted with tennis balls and oranges. Stanley Kubrick was so impressed that he cast Ermey as Gunnery Sgt. Hartmann.