Energy transfer vs tissue damage

[jackslayer]

So I've heard a lot of people talk about energy transfer being the most important thing and then others say it's tissue damage. One group says they don't want over penetration another says they want a bullet to pass through both sides. This is discussed both for self defense and hunting. Any experts out there that can clarify this? Thanks

 

[Balrog]

You are a little late to that party...

 

[General Geoff]

The point is to stop a threat, which can be accomplished in a number of ways. The most relevant three are:

1. Disrupt central nervous system.
2. Shatter a supporting bone structure (pelvis, femur, etc)
3. Exsanguinate the target (bleeding out).

Energy transfer is conducive to producing effects 1 and 2. Exit wounds are conducive to 3. Exsanguination should be noted as significantly slower to take effect than the other two, but is all but guaranteed if no medical attention is given.

 

[atblis]

The primary wounding mechanism of firearms is simply putting a hole in something. Nothing more, nothing less.

 

[jiminhobesound]

Somewhere there is a post by a coroner type discussing what he has seen with many bullet wounds that killed. I think his report is the most reliable and acceptable.

 

[NMGonzo]

Many holes going through the intended target around the thorax works well.

 

[Loosedhorse]

a post by a coroner type discussing what he has seen with many bullet wounds that killed.

A coroner's experience would be limited to those killed--even killed hours after being shot. An armed defender would be chiefly concerned with those stopped, stopped immediately, even if they survived.

A good boxer can drop most people with a punch to the jaw or midsection, and yet no "disruption" of the CNS or circulatory system (in the sense of a bullet wound) has occurred. So something besides penetrating wound tracts can in fact stop people.

The debate will continue about whether or not certain calibers and loads are better at incapacitating an attacker given a non-fatal hit--at this point it is chiefly a matter of opinion and philosophy. We will not get any dispositive facts any time soon.

Enjoy the debate, and decide for yourself. Most people on either side of the debate will tell you to carry the most powerful gun you can shoot accurately and quickly (and conceal, if applicable), and to load it with good factory HP ammo.

 

[Shawn Dodson]

A good boxer can drop most people with a punch to the jaw or midsection, and yet no "disruption" of the CNS...

The punch to the "jaw" causes the head to move suddenly and violently. The head moves but the brain doesn't. The cranium collides into the brain. The mechansim of collapse is blunt trauma directly to the brain.

Body hits produce internal blood lood loss. Blood flows into the abdominal/thoracic cavity. One or two holes on the outside don't make any difference in rapidity of incapacitation - it's what the bullet hits inside that counts.

The permanent cavity crushed by a handgun bullet is the primary wound mechanism. What structures the bullet pokes holes in determines how quickly incapacitation occurs.

"Permanent disruption" is all the tissue that is permanently damaged. It includes perment cavity and tears/ruptures and hyper stretched tissues produced by the bullet's temporary cavity. Rifle bullets usually produce greater permanent disruption than handgun bullets.

 

[mljdeckard]

Yep, think 'cavity trauma'. This is the one thing you can say with certainty a bullet will do. Make a hole. The more holes you make, the more likely it is that these holes will displace something critical to the target's motor activity. In this, pretty much any premium defensive round, 9mm or bigger will do the job, regardless of +P rating, etc.

While I think that the real world difference between calibers and brands matters much less in the real world than it seems to on the internet, I use .45 HSTs. They make holes about as big as you are going to get.

 

[Jeff82]

The Myth of Energy Transfer

http://www.firearmstactical.com/briefs3.htm

Don't get hung up on energy numbers. Energy is what allows a bullet to perform "work" so some is needed. That work is done by the bullet striking the target and damaging vital structures/organs within it. So long as the bullet can penetrate to the required depth and you can hit vitals organs that is all that is needed. Mushrooming bullets are preferred as they increase their striking (frontal) area. Energy beyond that needed to do this damage is wasted and results in less desirable effects such as longer followup shot time, more recoil, more muzzle flip, etc. This is for handgun class cartridges. The game changes significantly with rifle class cartridges (they add a temporary cavity that can cause damage too.)

 

[Loosedhorse]

blunt trauma directly to the brain.

No. Unless the cranial vault is broken, the mechanism is indirect trauma, caused by pressure waves in fluid and tissue. The same shock waves caused by "energy transfer."

Body hits produce internal blood lood loss.

You're saying that the incapacitation produced by a good boxer's body punch is due to "blood loss"? Or you haven't addressed that question?

Again, it is easy to say what will kill an attacker. What will incapacitate him may be different. We have many cases of people wounded nonfatally who stopped fighting, and a few of people who were fatally wounded, but kept right on killing people...for a while.

The question remains whether caliber and bullet choice have an influence on whether attackers (not hit in the CNS) stop fighting sooner than later. But I do understand that everyone has an opinion--opinions that (as I said) usually don't affect the final recommendations on which most people agree.

(Example: .357 Magnum out of 4 inch revolver--what's the preferred load for self-defense? Most everyone says 125 gr HP, so does it matter if it's energy transfer or tissue damage?)

 

[481]

So I've heard a lot of people talk about energy transfer being the most important thing and then others say it's tissue damage. One group says they don't want over penetration another says they want a bullet to pass through both sides. This is discussed both for self defense and hunting. Any experts out there that can clarify this? Thanks

Yep. Duncan MacPherson.

His book, Bullet Penetration is a solid technical read on the topic and addresses the fallacy of employing energy relationships to describe wound trauma incapacitation and soft tissue damage created by the passage of bullets through soft tissue.

"Energy Transfer" (aka: "Energy Dump" and "Blast Pressure Wave Theory") is a failed concept whose time has passed.

 

[Shadow 7D]

OH HO
another 'hydrostactic shock' going to blow up yer brains
v.s.
a gotta touch it to hurt.

How bout this happy medium
much like real estate
LOCATION LOCATION LOCATION
with the minor foot note, that it's 3D vs a 2D silhouette, so penetration is part of that.

 

[Malamute]

These discusions are often interesting, nearly always amusing to a point. I'm usually surprised (should I be?) by the number of comments from folks that I believe have not killed things before, or not payed much attention when they did kill things. Not saying that's the case in this thread yet, just saying,....

I for one would prefer to be slightly, or even way "overgunned" than under, given the choice. What may be "enough" in "most" cases, may not be enough in the one time it matters, to me (like say, a 6'4" 345 lb psycho). "Pretty good" doesnt sound as comforting as "outstanding" when I consider the issue.

I choose penetration and tissue damage. Energy may be a byproduct, but not the determining factor to me. I don't believe energy per se kills. How well a particular bullet functions is important. Round nose bullets perform very poorly compared to flat points, semi-wad cutters or working hollowpoints. Go kill some game with the various types and report back if you don't agree. Not wanting to cause conflict, just my observations after shooting game over a number of years with various guns and loads. I certainly don't mind if a particular bullet exits something. If it didn't, it may not go deep enough on a poor shot. I'd as soon a bullet go through anything I want to shoot from any angle, and no matter the size of the critter, and still expand well.

 

[McCall911]

A little story. But it's a bit graphic.

My Siamese cat Sadie (RIP) was a great hunter. She would catch almost anything that walked or crawled. Mostly they would be dead when she brought them to the house, but some would still be living (gifts of gratitude for the household, like lizards and non-venomous snakes.) One such living animal was a small rabbit. The rabbit was still living, although Sadie had bitten a large chunk out of its back. I don't think it could move its back legs. (Apparently she had deliberately disabled the animal so that she could transport him easier, but that's only a guess.)
Since I live in an unincorporated area, there was only one thing I could do. I had to put the poor animal out of its misery, but the only firearm I had was a 10mm handgun at the time. It was a S&W 1006 loaded with Winchester 175 grain Silvertips. (A pretty hot round.) After securing Sadie in the house, I shot the rabbit. The result was devastating to say the least.
Except for the head, the poor animal was reduced to a small mound of entrails. The bullet had apparently passed completely through the rabbit and into the ground, so it was not recovered. Since that's a pretty accurate description of the result, I will call this the end of my story.

So my two questions are: Was this massive damage *not* due to energy transfer? If there were no energy transferred to the animal, why then wouldn't there have been simply a smallish .40 caliber hole through the rabbit?

 

[mljdeckard]

There is a big difference between a bullet hitting a large object and a smaller object. The tissue that is stressed in a larger object will be torn in the smaller object because there is less to stretch. If there is less tissue to destroy with cavity trauma, the trauma will be more significant. If a bullet will do (x)cm3 of damage in a human-sized object, (x)cm3 of damage will appear greater in a smaller object because there is less to hold the object together. I've shattered plenty of jackrabbits with .45 HSTs. Even though they appear to shatter, there's nothing magical about it. It's just a hole.

 

[Sunray]

"...both for self defense and hunting..." Those are two very different things that have very little to do with one another. Hunting is about causing the least amount of pain to the animal you kill. Self-defence is about making a threat to your life go away. Isn't always about killing. Humans are not as tough as any game animal. Break a deer's leg with a bad shot, it just carries on. Break a human's leg/arm/rib, etc., they usually stop bothering you. Just damaging tissue doesn't guarantee anything. Neither does a through and through.
"...I shot the rabbit..." Ever think about stepping on its neck?

 

[McCall911]

"...I shot the rabbit..." Ever think about stepping on its neck?

No. I didn't want to hurt it.
Besides it's too late, by about 20 years!

 

[McCall911]

There is a big difference between a bullet hitting a large object and a smaller object. The tissue that is stressed in a larger object will be torn in the smaller object because there is less to stretch. If there is less tissue to destroy with cavity trauma, the trauma will be more significant. If a bullet will do (x)cm3 of damage in a human-sized object, (x)cm3 of damage will appear greater in a smaller object because there is less to hold the object together. I've shattered plenty of jackrabbits with .45 HSTs. Even though they appear to shatter, there's nothing magical about it. It's just a hole.

Good answer. Makes sense. Now I don't have to bring up the rabbit story anymore.

 

[The Lone Haranguer]

Is not the tissue damage a result of the energy transfer? For example, a FMJ that zips through a fleshy part of the body can hardly be said to have "transferred its energy."

 

[06]

Worked as an EMT many yrs and saw numerous bullet wounds-mostly handgun. Very few stopped the victim/assailant/subject in their tracks. Some walked/ran away to a phone, some continued the attack, and some panicked. Even with mortal wounds most lived many minutes. What stopped them quick were hits to the spine, kidneys, and head. One was shot 8 times and kept coming before a spine shot dropped him. Another, 14 times(22 rifle) and still took it away from the shooter(assailant). My solution: lots and lots of rounds then reload or a shotgun at close range. A shotgun stopped a perp who was kicking his way into a bedroom. She nearly blew his leg off. We got the bleeding stopped in time to save his life but the leg was to far gone. Good shot!!!!

 

[Deanimator]

I place NO confidence in "energy transfer" in a reasonably controllable handgun cartridge for self-defense.

I count on mechanical bone and tissue damage and blood loss.

 

[J-Bar]

Count me in with the "location" group.

Every day, in packing houses, I see 1000 lb bovines rendered unconscious by a .22 long rifle bullet between the eyes. Technically it does not kill them; it stuns them sufficiently that they are unaware of the knife stick that exsanguinates them. But the .22 is enough with precise placement (animal standing still, muzzle inches from forehead). The same .22 round shot into the animal's side, might not even penetrate the skin.

Deer hunters are often humbled by the absence of "knock down power" when they see that 120 lb. doe run a hundred yards after being hit with a high powered rifle.

I do not carry a handgun, and fortunately I have never had to defend myself with a firearm against another human. But it seems to me that choice of ammo and caliber for that situation is always a compromise. If you could place your shot precisely, even a .22 would work, but will you bet your life that you can place your shot that precisely?

 

[Shawn Dodson]

No. Unless the cranial vault is broken, the mechanism is indirect trauma, caused by pressure waves in fluid and tissue.

You're incorrect. The mechanism is direct trauma to the brain. The cranium slams violently into the brain.

You're saying that the incapacitation produced by a good boxer's body punch is due to "blood loss"? Or you haven't addressed that question?

The boxer falls down and either hits is head or his head violently moves from the impact - the mechanism is the same - physical collision between the brain and cranium.

 

[Shadow 7D]

Come on Shawn
you are being nice
(good read or two on ballistics if you check out his website)

You know he was talking about the mysterious pressure spike that comes from the majik boolit a .40/10-45 slamming into your toe or arm, and popping you brain like a champagne cork