Trapshooting is a sport in which a person shoots at clay disks that are thrown into the air by a machine. Trapshooters use a 12-gauge shotgun that fires shells holding about 500 lead pellets. The disks measure no more than 45/16 inches (11 centimeters) in diameter. A machine called a trap hurls the disks into the air at speeds of almost 60 miles (97 kilometers) an hour. The trap is housed in a structure called a traphouse, which is partially beneath the ground.