Hydrostatic Shock

[wes007]

I heard this was a myth.

What are your thoughts and concerns on it?

[Marcus L.]

This cut and paste generally sums it up for me:

"Physiologically, no caliber or bullet is certain to incapacitate any individual unless the brain is hit. Psychologically, some individuals can be incapacitated by minor or small caliber wounds. Those individuals who are stimulated by fear, adrenaline, drugs, alcohol, and/or sheer will and survival determination may not be incapacitated even if mortally wounded.

The will to survive and to fight despite horrific damage to the body is commonplace on the battlefield, and on the street. Barring a hit to the brain, the only way to force incapacitation is to cause sufficient blood loss that the subject can no longer function, and that takes time. Even if the heart is instantly destroyed, there is sufficient oxygen in the brain to support full and complete voluntary action for 10-15 seconds.

Kinetic energy does not wound. Temporary cavity does not wound. The much discussed "shock" of bullet impact is a fable and "knock down" power is a myth. The critical element is penetration. The bullet must pass through the large, blood bearing organs and be of sufficient diameter to promote rapid bleeding. Penetration less than 12 inches is too little, and, in the words of two of the participants in the 1987 Wound Ballistics Workshop, "too little penetration will get you killed." Given desirable and reliable penetration, the only way to increase bullet effectiveness is to increase the severity of the wound by increasing the size of hole made by the bullet. Any bullet which will not penetrate through vital organs from less than optimal angles is not acceptable. Of those that will penetrate, the edge is always with the bigger bullet."

-Agent Urey Patrick FBI from "Handgun Wounding Factors and Effectiveness"


I believe that in calibers that generate 1000ft-lbs or more of kinetic energy that there is significant enough temporary cavity stretch to cause trauma to surrounding organs that are not directly hit by the projectile or projectile fragments. However, even in a .44magnum which generates around 1000ft-lbs of energy, officers have had suspects take several hits to the torso and not immediately stop what they were doing.

There is really no reliable way to measure or demonstrate such effects even in real world shootings because of the great many factors that can corrupt the data. What can be measured and is the surest way to ensure good effects is to physically remove the largest swath of the badguy's anatomy as possible from vital regions of the body. So.......you want a well placed, large, deep penetrating hole.

The advice I usually give is for someone to shoot the largest caliber that they can shoot well in a timed course of fire in realistic scenarios. This usually means the selection of a common service caliber like 9mm, .40S&W, or .45acp. Going with more "powerful" handgun calibers offer no "measurable" improvement.

I generally prefer 9mm and .40S&W.

[wes007]

I appreciate your post.
Im fairly new to ballistics of service calibers because for the past couple of years my primary focus in firearms has been precision shooting.
That is a damn good point you made about your ability to shoot vs what you think has the greatest knockdown power.
I got into a tiny debate with a friend who is dead set on the idea that a .357 cartridge has more "knock down" power of any service caliber. When I watch him shoot his .357 he is all over the place. He's getting his hits in a combat effective zone but this is from a static position at 15yds.
Any advice on how I could mention to him some of the myths of knock down power

[Marcus L.]

Any advice on how I could mention to him some of the myths of knock down power

There's a lot of great articles out there by the International Wound Ballistics Association. Unfortunately, they no longer put out publications because they essentially accomplished their mission. They debunked the myths of energy dump, knock down power, hydrolic shock, and other snake oil theories with demonstrated scientific results........in the lab, and in the field with police officers, soldiers, and trauma surgeons.

Firearms Tactical has a lot of articles from the IWBA which you can find in their archives. A lot of skeptics will say that "oh, that's so 1999" and outdated. Last I checked the human body has operated the same way for the last 1-million years and there has been no significant advancement in firearms in the last 10-20yrs:
http://www.firearmstactical.com/tactical.htm

Here's some regarding energy dump/knock down power, and the problems with street shooting data:
http://www.firearmstactical.com/afte.htm
http://www.firearmstactical.com/briefs3.htm
http://www.firearmstactical.com/briefs8.htm

There's a LOT of great information on this website. You'll do yourself a great service if you take the time to read through it all.


Overall though, nothing has changed since the FBI pioneered wound ballistics science in the late 1980s following the 1986 Miami shootout where their 9mm 115gr ammunition failed to get the job done.

In regard to the .357sig, it isn't a bad caliber......it's just doesn't offer any measurable improvement over the 9mm in terms of actual trauma to the human body. Here's some testing data from Winchester Ranger Talons:

All testing is done in accordance with the standardized FBI protocols. The bare gel test involves 10% ballistic gel calibrated to mimic human muscle tissue. The other tests involve placing various materials in front of the bare gel to demonstrate what it would be like to shoot someone through such materials. After the bullet punches through these barriers it may become damaged /deformed or plugged with material(wood/cloth) which will reduce its expansion capabilities. When a hollow point expands it acts like a parachute reducing penetration. If it is damaged or plugged it may not expand very well which results in deeper penetration with less expansion. The FBI has done continued testing of ammunition for two decades and they take into account the results of actual street shootings and how that ammunition behaved against an actual person and/or barrier. With that knowledge, they still recommend that you use ammunition that achieves a minimum penetration depth of 12” in bare gel. They also conclude that good penetration is always more important than expansion, but as long as 12” of penetration can be maintained every bit of expansion improves terminal damage effects.

FBI Test Protocol:
Bare Gelatin = covered with T-shirt, Shot at 10ft
Denim = 4 layers shot at 10ft
Heavy Clothing = shot at 10ft
Steel = 2 pieces of 20 gauge, shot at 10ft
Wallboard = 2 pieces of 1/2" gypsum board, shot at 10ft
Plywood = 1 piece of 3/4" AA fir plywood, shot at 10ft
Automobile Glass = 1 piece of 1/4" laminated safety glass set at a 45 degree angle with an offset of 15 degrees, shot at 10ft

.380 95gr(1000fps): (Penetration/Expansion)
Bare Gel: 7.65”/.65”
Through Denim: 7.95”/.64”
Through Heavy Cloth: 7.85”/.64”
Through Wallboard: 15”/.36”
Through Plywood: 15.5”/.36”
Through Steel: 9.3”/.36”
Through Auto Glass: 4.5”/NA

9mm+P 124gr(1180fps): (Penetration/Expansion)
Bare Gel: 12.2”/.66”
Through Denim: 13.9”/.67”
Through Heavy Cloth: 13.3”/.68”
Through Wallboard: 14”/.66”
Through Plywood: 13.1”/.65”
Through Steel: 18.9”/.40”
Through Auto Glass: 10.6”/.48”

9mm+P+ 127gr(1250fps): (Penetration/Expansion)
Bare Gel: 12.3”/.64”
Through Denim: 12.2”/.68”
Through Heavy Cloth: 12.2”/.68”
Through Wallboard: 12.1”/.66”
Through Plywood: 12”/.68”
Through Steel: 20.5”/.40”
Through Auto Glass: 9.4”/.48”

9mm 147gr(990fps): (Penetration/Expansion)
Bare Gel: 13.9”/.65”
Through Denim: 14.5”/.66”
Through Heavy Cloth: 14”/.66”
Through Wallboard: 15”/.67”
Through Plywood: 14.8”/.62”
Through Steel: 17”/.45”
Through Auto Glass: 10.8”/.52”

.357sig 125gr(1350fps): (Penetration/Expansion)
Bare Gel: 10.9”/.63”
Through Denim: 12.1”/.66”
Through Heavy Cloth: 10.7”/.69”
Through Wallboard: 15.4”/.48”
Through Plywood: 12.2”/.66”
Through Steel: 23.4”/.41”
Through Auto Glass: 10.3”/.49”

.40S&W 165gr(1140fps): (Penetration/Expansion)
Bare Gel: 12.7”/.72”
Through Denim: 13.2”/.70”
Through Heavy Cloth: 14.3”/.68”
Through Wallboard: 11.4”/.69”
Through Plywood: 13.1”/.71”
Through Steel: 20.4”/.48”
Through Auto Glass: 11.3”/.61”

.40S&W 180gr(990fps): (Penetration/Expansion)
Bare Gel: 13.6”/.71”
Through Denim: 13.9”/.68”
Through Heavy Cloth: 13.3”/.67”
Through Wallboard: 13.4”/.67”
Through Plywood: 15.3”/.65”
Through Steel: 15.8”/.58”
Through Auto Glass: 12.3”/.60”

.45acp 230gr(905fps): (Penetration/Expansion)
Bare Gel: 12.4”/.76”
Through Denim: 12.9”/.73”
Through Heavy Cloth: 12.5”/.74”
Through Wallboard: 15.0”/.72”
Through Plywood: 16.4”/.53”
Through Steel: 15.3”/.55”
Through Auto Glass: 12.2”/.61”

.45acp+P 230gr(990fps): (Penetration/Expansion)
Bare Gel: 13.2”/.79”
Through Denim: 15.2”/.78”
Through Heavy Cloth: 15.7”/.78”
Through Wallboard: 13.8”/.75”
Through Plywood: 14.6”/.77”
Through Steel: 20.6”/.53”
Through Auto Glass: 13.6”/.60”


These are pretty typical performance numbers for most of the modernized ammunition brands on the market and their perspective calibers.
http://i480.photobucket.com/albums/rr169/sgalbra76/Handgun_expanded_JHP.jpg

[wbm]

"Kinetic energy does not wound. Temporary cavity does not wound."

LOL!:D A projectile absent kinetic energy does not wound and there is no "temporary" wound cavity. Jeeeez guys get real.

[DocGKR]

Perhaps you are misunderstanding what was stated above--kinetic energy is certainly important, as it is what allows the projectile to do work, however, in itself kinetic energy is not a wounding mechanism. On the other hand, temporary cavity is certainly an important wounding mechanism, especially in rifle calibers, as well as larger handgun calibers, however, with service handgun calibers, it is generally too small to cause significant wounding effects.

[WS6]

Perhaps you are misunderstanding what was stated above--kinetic energy is certainly important, as it is what allows the projectile to do work, however, in itself kinetic energy is not a wounding mechanism. On the other hand, temporary cavity is certainly an important wounding mechanism, especially in rifle calibers, as well as larger handgun calibers, however, with service handgun calibers, it is generally too small to cause significant wounding effects.

This reminds me of discussions of "Horsepower vs. Torque" regarding drag-racing. Without torque, all the horsepower in the world won't do any good, and without horsepower, you're going to lose the race. You need BOTH. There have been studies done that show that kinetic energy of a very specific amount is required for the penetration of skin and bone, yet this energy does not wound, the disruption of these tissues by the projectile wounds, yet it cannot disrupt them if it does not have the energy to do so. It hurts my head at times as well.

[DrJSW]

This reminds me of discussions of "Horsepower vs. Torque" regarding drag-racing. Without torque, all the horsepower in the world won't do any good, and without horsepower, you're going to lose the race. You need BOTH. There have been studies done that show that kinetic energy of a very specific amount is required for the penetration of skin and bone, yet this energy does not wound, the disruption of these tissues by the projectile wounds, yet it cannot disrupt them if it does not have the energy to do so.

Your analogy is an excellent one. Thanks.