Great emphasis is placed on the lethality of modern high-powered street weapons, and their impact on mortality from firearm injuries. Presented is a case of an air rifle BB injury to the chest, resulting in a penetrating injury of the right heart, with apparent retrograde embolization to the inferior vena cava. Although no clinical evidence of pericardial tamponade was present 4 hours following injury, 150 mL of pericardial blood was encountered at median sternotomy, secondary to a right atrial appendage entry wound. This case exemplifies three important principles regarding penetrating chest trauma and air guns: (1) Modern air rifles, capable of muzzle velocities as high as 900 fps, are intrinsically lethal weapons; (2) missiles within the cardiovascular system have a propensity for embolization, and often follow an intuitively unexpected course; and (3) young healthy patients with potentially lethal penetrating cardiac injuries, particularly those caused by low velocity firearms, may appear stable and minimally injured in the emergency room. A strong suspicion of cardiac injury and prompt intervention should be extended to airgun injuries of the thorax.