bullets arrows and knives all kill the same way.


copied and pasted.

Since the understanding of what causes effective wounding is prerequisite to any discussion of the desired terminal performance of a bullet, let us first examine the mechanisms of wounding which result in incapacitation and death.

Rapid death is brought about only by brain death (i.e., the collapse of the central nervous system). Brain death can be caused directly by damaging the brain or upper spinal tissue, or indirectly by depriving it of oxygen. Oxygen deprivation is the result of cardiac arrest or of hemorrhaging which reduces blood pressure or damage that completely shuts off the circulatory function. Thus rapid death is accomplished by causing the collapse of the central nervous or circulatory systems.

The single most important factor in wound lethality is bullet placement. This cannot be overstated. It is true that sometimes a direct hit on the brain by a bullet is not instantly incapacitating (read Massad Ayoob's "terminator" story from several years ago), but generally this is because that portion of the brain struck is the relatively "unimportant" part associated with cognition. Hits against the base of the brain or the upper spine are almost always instantly fatal because these regions control the involuntary vital functions like heartbeat and respiration.

In the case of hemorrhage resulting from damage to the lungs or arteries, brain death will likely occur prior to cessation of cardiac function; the time required for brain functions to deteriorate to the point of unconsciousness depending on the rate of hemorrhage. However, when damage is done directly to the heart, the circulatory function may be arrested first, leading to unconsciousness within a few seconds. There is another mechanism of cardiac arrest that is less well understood but which may account for the nearly instantaneous death of game animals hit with modern weapons and that is induced cardiac fibrillation and arrest. The precise mechanism for the onset of the cardiac arrest is not fully understood, but its effect is well documented. It may involve some type of local neurological or humeral communication between the heart and lungs that gets short-circuited. Alternatively, a violent wound to the lung tissue may create a tiny embolism that interrupts cardio-pulmonary function at a critical moment.

Other than hits to the central nervous system (brain and spine) or the unpredictable mechanism of spontaneous cardiac arrest, the only reliable cause of rapid death is through hemorrhaging produced by cutting a hole through major blood-bearing organs (heart, lungs, liver) or major blood vessels (e.g., aorta). The dimensions and especially the location of the cavity produced by the bullet will determine the rate of hemorrhaging and in turn the rapidity of the onset of death. It is actually more lethal in some cases to sever the arteries directly above the heart, than to penetrate the heart itself. If these arteries are cut, blood pressure instantly drops to zero and death will follow in seconds (this is one reason why an arrow can kill as fast as a bullet). Lethal hemorrhaging does not depend upon how much blood exits the body, but only upon the loss of blood pressure. A bullet which exhibits both expansion and deep penetration is desired. Three things are worth noting: 1) hemorrhaging in the thorax is far more severe in the case of pneumothorac injuries (collpased lung) than in vascular tissue such as muscle, due to the relative pressure difference between the pleural space and the cardio-vascular system, 2) the surface area of the wound, not its volume, is most related to the rate of hemorrhage, and 3) the body's natural response to hemorrhage, coagulation, is more pronounced in extremely violent wounds which rupture thrombocytes, releasing fibrin into the blood (in other words very sharp cuts generally bleed more freely and longer than ragged, macerated wounds - although a cleanly severed artery may spasm and close, whereas a torn artery may continue to bleed).