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A quote from the above link, that may go somway to exlaining fatboy404's experience in the field

The other popular contemporary misconception results from the assumption that the kinetic energy of the bullet is "transferred" to the target, thereby somehow killing it through "hydrostatic shock".

I don't know where this term originated, but it is pseudoscience babble. In the first place, these are dynamic - not static - events. Moreover, "hydrostatic shock" is an oxymoron. Shock, in the technical sense, indicates a mechanical wave travelling in excess of the inherent sound speed of the material; it can't be static. This may be a flow related wave like a bow shock on the nose of a bullet in air or it may be a supersonic acoustic wave travelling through a solid after impact. In terms of bullets striking tissue, shock is never encountered. The sound speed of water (which is very close to that of soft tissue) is about 4900 fps. Even varmint bullets do not have an impact velocity this high, let alone a penetration velocity exceeding 4900 fps. Unless the bullet can penetrate faster than the inherent sound speed of the medium through which it is passing, you will not observe a shock wave. Instead, the bullet impact produces an acoustic wave which moves ahead of the penetration. This causes no damage.

Some people use "shock" in the colloquial sense to describe a violent impact, but it is confusing, especially in connection with the term "hydrostatic" and lends undeserved quasi-scientific merit to the slang. It also tends to get confused with the medical expression attending trauma. We are not describing any medical shock. The word shock should never appear in a gun journal.

Before I become too dogmatic and overstate the situation, let me concede that there may be some merit to the idea that hydrodynamic (not hydrostatic) impulse created by bullets which have a high kinetic energy and generally exhibit violent cavitation, can cause some secondary effects due to pressure on the nervous system or heart. It is possible to kill manually by nerve "strangulation". In this case actual damage to the central nervous system is not caused, but the signals governing the heart or diaphragm are shut off, resulting in instantaneous unconsciousness or even death. This sort of thing makes for lurid mythology in the martial arts and bad movies, but there is some real science behind it. Certain rare sports fatalities have been definitely attributed to a swift blow which interrupts the cardiac rhythm. Acoustic pressure on the spine can also cause temporary paralysis. These phenomena may account for the rapid effectiveness of some high-velocity hollow-point pistol bullet wounds, especially in cases in which the victim is not mortally wounded and recovers consciousness within a few minutes. Several special handgun loads have been designed with no regard whatsoever to penetration (e.g., the THV bullet) in order to achieve this result. Unfortunately, this is an unreliable mechanism of incapacitation, generally obtained at the expense of effective penetration. No bullet yet designed will produce this effect even 10% of the time. Many of the bullets designed to use this effect can be defeated by common barriers, such as glass, sheetrock, and even clothing. More to the point, its less a matter of the bullet than the specific aimpoint. Doing this deliberately by hand, even with a profound understanding of the mechanism and vital points, is extremely uncertain; using the passage of a pressure wave from a bullet to accomplish this falls into the freak event category. Such is never an acceptable mechanism for the hunter.

The point that I have attempted to press here (perhaps in a rambling fashion) is that complete penetration is not something to avoid in the hunting field. In fact there is good evidence that through and through wounds cause collapse quicker in many instances, especially lengthwise shots.

On the other hand, as I have alluded to previously, some contemporary bullet designs (Nosler Ballistic Tip and Remington Bronze Point) as well as some renowned performers from years past (e.g., the original 130 gr. load of the .270 Winchester) achieve a high percentage of instantaneous kills by blowing to bits and never exiting the game. I find this interesting in view of the current obsession with avoiding bullets in which the lead cores separate from the jacket. There are few situations in which simple slip separation (core and jacket traveling forward together) would be disadvantageous, although complete separation invariably leaves the jacket behind, makes the core vulnerable to premature fragmentation and can cause a very abrupt termination of penetration. But returning to the issue, the successful frangible bullet designs nevertheless always penetrate to the vitals and have never been regarded as reliable for rear raking shots requiring deep penetration or against very tough heavy game and most knowledgeable authorities prefer bullets which exhibit modest cavitation with deep penetration because of their flexibility in the field.

Edited by Mcleish (14/07/10 06:46 PM)

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