The 39-year-old died in hospital on Monday night after being shot in the head at the firing range in White Hills, which is 60 miles outside of Las Vegas.
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Vacca lost his life after the girl's gun recoiled
Charles Vacca had been demonstrating the automatic Uzi to the girl when the accident occurred.
According to witnesses, the girl pulled the trigger and the recoil sent it over her head, and Charles, who was standing next to her, received a shot to the head.
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A military veteran, Vacca had been working at the firing range for two years, and had not been involved in any other accidents since beginning his job there.
The girl's parents were recording the tutorial on their mobile phones when the tragedy occurred, and handed the footage over to authorities after the incident.