Early in my medical training, I learned that it is not the bullet that kills you, but the damage from the bullet. A handgun bullet enters the body in a straight line. Like a knife, it damages the organs and tissues directly in its path, and then it either exits the body or is stopped by bone, tissue or skin.
This is in contrast to bullets from an assault rifle. They are three times the speed of handgun bullets. Once they enter the body, they fragment and explode, pulverizing bones, tearing blood vessels and liquefying organs.
This is what was happening to my patient, whose heart quickly stopped beating. We performed an emergency thoracotomy — splitting open his chest in an attempt to clamp off bleeding and restart his heart. Blood poured out of his chest cavity. The bullet had disintegrated his spleen and torn his aorta. Four ribs had essentially turned to dust. The damage was far too extensive. He died in our E.R. He was 15.