This compilation is from my own observations in the field, thinking, understanding of physics - as well as reading the many articles on the subject. The photos are from GS Custom Bullets website: shooting a 40gr bullet at 4,700 ft/sec from their 5.56x64 from 80 yards proving that even very high velocity does not cause meat damage. The similar shots from a .243W and 95gr bullets showed 4x larger and deeper tissue damage. Inside wound channels of the .224 bullet were without blood vessel damage - only entrance and exit wounds where resistance from the elastic skin and thus momentary bullet slowdown was experienced showed damage in the outer membrane.
Hydrostatic Shock: What are we talking about?
“Hydrostatic shock” proposes the theory that an animal’s remote organs can be fatally damaged by a pressure wave through the body’s tissue fluid (mostly blood which is given its fluidity by water) caused by a bullet entering anywhere into an animal’s flesh and sending a shock wave in all directions. This hypothesised fatal organ damage would be in addition to the mechanical damage from direct contact between the penetrating projectile and directly adjacent tissue. This fatal shock wave propagation supposedly could start from a very fast bullet hitting anywhere on the beast’s body - including the rear knee, as has already been proposed elsewhere.
The “static” in “Hydrostatic shock” refers to a fluid which is not in motion and acted on by an outside force. “Hydrodynamic shock” would refer to the pressure force of a fluid in motion impacting on an outside body in its path.
The "shock" in the term "hydrostatic shock" refers to the physiological effect on remote tissue and not to the characteristics of the “shock wave”. That is a pity and already indicative of the incorrectness of the concept. In no way do gun writers or ammunition manufacturers attempt to explain where and how such a shock wave could have been caused originally. The reason they do not is because that physical fact will steer the discussion away from the hydrostatic dogma.
The object of the hunter is to kill his animal as quickly as possible. It is not to incapacitate it for a while - during which:
the hunter can bring his unfit body close enough to the animal for a blow of mercy, or
the animal slowly expires due to inhaling and ingesting its own blood via cuts into the trachea by bullet slivers, (which I have often seen happening to deer in Colorado), or
the animal slowly expires due to suffocation because of large cuts by bullet slivers through its diaphragm, or
A combination of the above (the most evident cause of unnatural death amongst deer in my observations), or
The animal slowly expires due to a traumatic drop in blood pressure and brain hypoxia due to a massive leak caused by “hydrostatic shock” having burst open an artery brittled by Atherosclerosis. (only, animals do not suffer from this cardiac disease - so their arteries are exceedingly elastic and flexible...), or
The animal slowly expires due to a traumatic drop in blood pressure and brain hypoxia due to a massive blood leak caused by the bullet having mechanically cut open the oxygen rich liver and often the gall bladder, while the actively pumping heart having been triggered and sustained by massive amounts of adrenaline puts a lot of bad smelling and bad tasting blood into the body cavity (the second biggest cause of deer deaths).
So how does hydrostatic shock purportedly kill an animal?
When confronted with the fact of the tremendous elasticity and resonant condition of arteries and in fact all body cells in all wild animals, the truly (dis)ingenious response by the preachers of the dogma can be summarised as this: The energy impulse causes a spike in blood pressure because the shock wave via the body tissues around the main blood vessels momentary compresses all the main arteries and veins, and this causes a sudden rise in BP which is sufficient to cause remote capillaries in the brain to burst. I kid you not.
Of course that explanation of flexibility of membranes denies the very principle of their hydrostatic dogma - which by the way is a real concept in true physics. BUT: A hydrostatic shock wave only can exist and be propagated where there is VERILY no compression possible of the media through which the shock wave must travel.
Also, for the above physical actions to take place and execute their fatal physiological effects on whatever organs, the well known principle of ”hydraulic shock” needs to be in action and not the concept of hydrostatic shock; the latter is how a depth charge fractures the hull of a submarine suspended inside the same fluid within which that massive explosive charge is detonated. Rifle and ammunition manufacturers simply insult the intellect of the users of their products by applying the wrong term to their sales points and then lie about the physics surrounding it.
As soon as one proposed principle of the dogma is refuted, true to their learned style the apologetics will conceive another one, as was related above. Like with all dogma there never is a unified theory which will stand scrutiny. Here is yet another one they want you to simply (like a child) just believe in: The shock wave propagation to remote blood vessels is often related to an automobile’s hydraulic braking system. The temporary cavity caused by a bullet’s passing is likened to the brake pedal and the remote organs seen as the brake pads. This flawed argument based on a sealed system with very rigid, very small diameter brake lines ignores the tremendous elasticity in an animal’s vascular system and cell structure as mentioned earlier. The shock front from the bullet's temporary cavity is not simply passed along through the blood vessels as it is when you step on a brake pedal, but it is dissipated within the living tissue as the pressure moves laterally away from the wound channel.
The hydrostatic shock theory is mostly based on high velocity, but apart from the immediate impact area where bullet slow-down occurred the hunter who dresses his own animals will never observe cell rupture inside the wound channel. That tissue is quite intact apart from the mechanical cutting caused by the bullet. I have many times shot small game like bushbuck and duiker for camp meat with 300 gr .375 H&H and 400 gr .416 Rigby monolithic solid bullets that simply zipped through the shoulders and the heart without any resistance or slow-down and there is never any blood vessel rupture inside that wound channel even while tremendous kinetic energy values are present in the bullets and hydrostatic shock should be massive.
If this high speed passing through does not rupture blood vessels or tissue cells adjacent to the bullet, then this sceptic heretic understands the physics that it can not occur in the brain or liver a few feet away.
40 gr .224 GS Custom Bullet from 5.56x64 GSC with 4,700 ft/sec muzzle velocity
Hydrostatic shock does not kill. So what does?
A direct hit to the animal’s brain or central nervous system will immediately terminate all brain function, so this is the best shot. Not too many hunters feel confident that he could successfully hit the brain, but even so he must still employ other means to stop the animal’s brain activityand that is damage the number one vital organ - the heart. The moment the heart stops two things happen:
the animal’s blood pressure rapidly drops.
When there is a sufficient drop in blood pressure, blood supply to the brain ceases or slows and the brain ceases to function. This is the quickest and most reliable body shot to kill any animal. Death is not instantaneous but the damage should stop the animal’s brain function in less than 15 seconds if it had not seen you before the shot. The adrenaline rush to the neuro sensors caused by that shock of seeing a predator no doubt will ensure a longer and stronger heart beat time - but 60 yards appear to be the maximum it should run.
Many arguments promoting hydrostatic shock as the killing mechanism caused by fast bullets are sadly physiologically, medically and intellectually dishonest. Like with the improper promotion about the killing effects of kinetic energy it appears is as if people desperately wish to believe the amorphous claims of these entities’ function in bullet behaviour, and care little for the value of clear thinking.