14 year old boy accidentally shot by hunting gun

A 14 year old Washington boy was accidentally shot in the arm when a hunting gun bumped around in a car and discharged:

 A 14-year old boy was accidentally shot on Monday while on a hunting trip with his father, according to Lewis & Clark County Sheriff Leo Dutton.(...) 

According to Sheriff Dutton, the teen had not been hunting before. He used a magazine drop to unload the weapon. It became apparent later, however, there was still one shell in the chamber.

On the drive back to camp, the son had placed the butt of the gun on the vehicle floor and the muzzle toward the roof. They hit a bump causing the rifle to discharge.

The bullet struck the son in the right bicep, exiting the right shoulder. The bullet exited the roof of the pickup truck.