When a shotgun is discharged into the head during a contact (loose or hard) or close range shot (up to about 15-30 cm or 6-12 inches), the pellets contained in the cartridge have not had time to spread, and they enter the body as a single mass.

Where the barrel of the shotgun is in hard contact with the head, a large volume of gas also enters the cranium - the effect of which is one of massive destruction.

The explosive effect disrupts the cranium and its contents, so that pieces of skull and brain tissue are spread over a wide area.