The sheriff's office said the girl had successfully fired the 9mm machine gun on single-shot mode, but when the weapon was switched to full auto, it recoiled and she lost control. Vacca, who was standing to her left, was hit with "an undetermined number of rounds."
Vacca was airlifted to a Las Vegas Hospital, where he died Monday night.
The Review-Journal notes that fully automatic weapons are a selling point on the Burgers and Bullets website:
"Our guests have the opportunity to fire a wide range of fully automatic machine guns and specialty weapons," the website states. "At our range, you can shoot FULL auto on our machine guns.
"Let 'em Rip!"
The girl and her family were on vacation from New Jersey. The sheriff said no charges will be filed, and the shooting range won't be cited because it's "licensed and legal."