Romper Stomper

A gang of violent neo-Nazis from Footscray, Victoria, Australia, attack three teenagers, in a tunnel at Footscray Station. The gang is led by Hando and his friend and second-in-command, Davey. They meet Gabrielle the day after her sexually abusive, highly affluent father Martin, has her junkie boyfriend arrested, Gabrielle starts a romantic association with Hando. Friends visit from Canberra; one of whom has joined the Royal Australian Navy A party at the warehouse follows, the next day two boys go to their local pub. Unbeknownst to them, the owner has sold it to a Vietnamese businessman. Upon seeing the new owner and his sons, they inform Hando and he and his gang arrive and savagely beat the new owner's sons. A third Vietnamese youth phones for help, before Tiger and several armed Vietnamese men descend upon the skinheads. The Vietnamese outnumber the skinheads and force them to retreat to their rented warehouse, where the Vietnamese ransack the building before setting it on fire.
The skinheads find a new base at a nearby warehouse, after evicting a pair of squatters, and plan their revenge against the Vietnamese. Learning that gang members plan to buy a gun, two female friends of the gang depart. Gabrielle suggests the gang burgle her father's mansion. They ransack the house, beat up Martin, smash one of his cars, and raid his wine collection. Gabrielle tells Martin the burglary is revenge for his years of abuse. Gabrielle reveals to Davey her plan to take Hando away from his violent life. Martin frees himself and uses a handgun to scare away the gang before they can take any of his property. Davey begins to have doubts about his violent lifestyle.
Gabrielle criticizes Hando's handling of the robbery, and he abruptly dumps her. Davey announces his intention to leave at the same time and gives Gabrielle his German grandmother's address, where he will be staying. However, Gabrielle informs the police of the gang's location and then spends the night with Davey. However, Davey reveals his doubts about his violent lifestyle, having removed the racist patches from his flight jacket out of concern for his grandmother.
While Hando is out, the police raid the warehouse and youngest skinhead is shot in the head after pointing a deactivated gun at the police. The police arrest the rest of the gang. However, Hando watches from a distance and flees.
Arriving at Davey's flat, Hando finds his friend in bed with Gabrielle. Hando accuses her of informing the police, but Davey says they were together the whole time since leaving the squat. Hando convinces Davey to stick by him, and the trio go on the run. They rob a service station, before Hando strangles the Asian attendant to death; and, driving all night, they stop at a beach. The next morning on the beach, Gabrielle overhears a conversation wherein Hando tries to convince Davey to leave her behind. Gabrielle sets their car on fire and admits to phoning the police. Hando attacks her, attempting to drown her in the surf. However, Davey stabs Hando in the neck with his Hitler Youth Knife. After the fight, Davey cradles a horrified Gabrielle, watched by a busload of Japanese tourists; and Hando gazes at the ocean as he bleeds to death.

Question: What does Martin use to scare away the gang?
Answer: Handgun