Lipstick

Chris McCormick is a highly paid fashion model whose image serves as the driving force of the ad campaign for a popular brand of lipstick and can be seen in magazines and on billboards all around the world. Gordon Stuart, a part-time composer and full-time music teacher, eagerly accepts Chris's 13-year-old sister Kathy's invitation to come to a secluded beachside photo shoot, so Chris can listen to some of his music. He arrives at her apartment one day to visit her, but is interrupted by a phone call from her lover, Steve Edison.
As Chris talks to Steve, Gordon begins to fume at the thought of Chris' obvious rejection. His hurt soon turns to anger, and he enters her room and smashes a picture of her brother Martin, a priest, before throwing himself on top of her. During Chris's struggle to fight him off, Gordon slams her head against one of her bedposts and screams at her to show him where she keeps the lipstick that her face sells to the public. When she tells him it is in her bathroom, he takes her in there and smears it across her face, then forces her to perform fellatio on him to leave the traces of the lipstick on his genitalia. Returning her to her bed, he ties her down with silk scarves, and anally rapes her to the accompaniment of his discordant compositions. Near the end of the ordeal, Kathy returns home from school and walks in on Chris and Gordon, and flees. He gets up and suggests Kathy join them and "have some fun," but instead cuts Chris free and leaves.
Gordon is arrested, but as Chris learns from Carla Bondi, the prosecutor assigned to handle the case, Gordon's conviction is hardly a sure thing, and she asks her to testify against him. Gordon's attorney argues that the sex was consensual, and that its roughness was the result of Chris's own twisted desires. He also suggests that even if Gordon acted without her consent, she provoked him by appearing naked in front of him at the photo shoot where they first met, and by the inherent sensuality of the photographs from which she makes her living. Gordon is ultimately acquitted.
Chris leaves her job modeling for the lipstick company, and plans to relocates to Colorado with Kathy after her last shoot. By a terrible coincidence, Kathy's old school is using the same building where Chris's shoot is to rehearse a new ballet being orchestrated by Gordon. As Chris poses in a red sequined gown, Kathy runs into Gordon, whoâdespite her protestations to the contraryâa part of her still believes is innocent. Gordon chases her through the abandoned building and rapes her.
Kathy returns to the photo shoot and tells Chris what happened. Chris, in a frenzy runs outside to her car and grabs a Remington Slide-Action Rifle she had intended to take to Colorado with her. Chris spots Gordon driving his car in the parking lot, and shoots at it. Gordon is hit by a bullet. He tries running Chris over, but the car swirls and overturns on its side. As he climbs out of the car, Chris shoots him three times. As he convulses, Chris approaches his body and shoots him in the groin, and continues to shoot his corpse. Later, Carla Bondi speaks to a jury, telling them that their acquittal of Gordon earlier resulted in Chris losing faith in the law. The jury ultimately finds Chris not guilty.

Question: What does Chris use to kill Gordon?
Answer: Gun