Four family members were in a remote area when one of the men was killed after his gun misfired, said Sgt. Spencer Cannon, Utah County Sheriff's Office.
They were shooting rifles in an area called Manning Canyon between Eagle Mountain and Fairfield.
One of the men was holding his rifle upwards, preparing to shoot, when the gun misfired hitting 24-year-old Joshua Hooper in the back of the head, said Cannon.
Cannon said after medical crews arrived, Hooper was pronounced deceased.
Police say there was nothing suspicious about the death and declared it an accident.