State police Joseph V. Loughrey, 44, of Sharpsville, was putting a handgun in a truck outside Trig's Reloading Den in East Lackawannock Township in Mercer County just before 11 a.m. when the 9mm Taurus pistol fired, striking his son Craig in the chest. The boy died at the scene, the Pittsburgh Tribune-Review reported.
Police said Loughrey told them he had emptied the gun's magazine but didn't realize there was a round in the chamber.
The newspaper said Loughrey had gone to the store to try to sell the handgun and a rifle. After the shop owner declined to buy them, Loughrey and his son returned to the truck. He put the boy in a booster seat, placed the rifle in the truck and as he reached to put the handgun in a center storage console it fired, state police said.
Authorities were investigating the shooting as an accident, but state police Lt. Eric Hermick said Loughrey could face charges such as manslaughter or negligence.