Energy Dump - A Self-Defining Term

[GaryArkansas]

I looked at a couple of threads tonite, and I keep seeing a couple of terms repeated - energy dump and energy transfer. I thought these ideas were debunked in the mid 1990's?

Bad guys do not fall down because one bullet has more kinetic energy than another bullet.

Kinetic energy, also called energy transfer, does not, by itself, kill bad guys. It does not knock them down. It is not, by itself, a man stopper.

"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."

Overpenetration - realistically, its just not an issue. "... virtually none have ever been sued for hitting an innocent bystander through an adversary. On the other hand, tragically large numbers of officers have been killed because their bullets did not penetrate deeply enough."

http://www.thegunzone.com/quantico-wounding.html

Your comments?

 

[The_Antibubba]

Temporary cavity does not wound.

But it can have a debilitating effect on nerve tissues, right?

 

[fletcher]

Keep in mind that I'm talking about handguns in all of the following:

I believe that your stop/kill/injure/whateveryouwanttocallit is a function of many variables. The easiest ones to measure are energy, momentum, initial diamer of the round, and final diameter of the round. Most everything else is an approximation (even ballistic gelatin), regardless of accuracy.

I also believe that after you reach a caliber capable of sufficient penetration and hole-making ability, "Bad guys do not fall down because one bullet has more kinetic energy than another bullet" is true. But, energy transfer results in failure of materials, including human tissue.

Penetration is probably the #1 requirement, I won't argue that.

As far as I knew, "knock down power" was completely figurative. It was just terminology for "will the BG go down after he gets shot with ___" a time or two. No handgun round will result in a literal knockdown on a grown person. Sounds like this was taken a little too seriously.

Now shock, hrm, that's debatable. I understand that some people who might know they have been shot might have a mental reaction to it, causing them to cease what they're doing and essentially go into shock. I would not use this as a given when choosing ammunition or anything else.

I definitely believe that the temporary cavity has an effect on overall damage because of the stresses associated with it. However, it may just be proportional in some manner to the size of the permanent cavity, and not really have much significance.

The only true stop will come from a sucessful CNS hit. Everything else is banking on causing mental shock, which results in the BG going down, or physically incapacitating the BG by blood pressure drop - passing out.

Bottom line - carry something sufficient, shoot what you carry well, and all of this arguing won't matter.

 

[Hook686]

hmmmmm .... from "

"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."

,

it sounds to me as though you are postulating penetration to be independent from the kentetic energy of the projectile. Does it not take energy to break the bonds of the tissue, and bones on its way to the "large, blood bearing organs"?

 

[silversport]

isn't that what you take after a Cliff Bar???......serioulsly...No one has ever been sued for hitting a bystander after the bullet went through a baddie??? Mas Ayoob talked about LEOs being sued from time to time...not sure if it was true but I'm just sayin'...I will agree that too many people put too much faith in the terms that some experts throw around....22LRs have "knocked down" people from fright and .45ACPs have failed to do the same on determined individuals...so...

Bill

 

[GaryArkansas]

True enough - you must have sufficient kinetic energy for the projectile to penetrate tissue. What I'm talking about is the concept that the momentum of a handgun round will physically injure someone, as distinct from the trauma caused by the crushing and tearing from direct projectile contact.

A Randy Johnson fastball has way more kinetic energy than any handgun round. If "energy dump" is to be accepted as truth, then he should've killed several opponents by now.

Unless body tissue is actually torn, as occurs with a high velocity rifle round, the body shrugs off a handgun's temporary cavity pretty quickly. Think about the times you've whacked your thumb with a tool, or stubbed your toe on a door frame.

It smarts, true enough. However, your finger or toe was probably not permanently damaged, and you were able to walk it off. The amount of kinetic energy transmitted by a handgun round is probably not too far off those scenarios (although much more focused in its location and duration).

 

[jon_in_wv]

Of course kenetic energy wounds. See how effective a bullet with 300 lbs of STORED energy is.

 

[Lone_Gunman]

What I'm talking about is the concept that the momentum of a handgun round will physically injure someone, as distinct from the trauma caused by the crushing and tearing from direct projectile contact.

Momentum injuring someone? What does that mean? Please explain. I have been treating gunshot wounds for about 15 yrs and have never seen an injury from momentum.

Momentum helps with penetration, and penetration wounds by crushing, cutting, and tearing.

But there is no distinct injury from momentum that can be seperated from that.

 

[W.E.G.]

It is the momentum of the mythical concept of "knockdown power" that is most formidable.

Even after all these years, and despite all the science, the term is still used by people who should know better.

 

[Kentak]

Momentum injuring someone? What does that mean? Please explain. I have been treating gunshot wounds for about 15 yrs and have never seen an injury from momentum.

Are you a physician, then?

Ever see a gunshot wound caused by a bullet with zero momentum?

Perhaps you are playing with semantics. Gunshot wounds are caused by bullets. But, bullets that have more momentum are more likely to cause more serious wounding, all other things being equal.

K

 

[mavracer]

A Randy Johnson fastball has way more kinetic energy than any handgun round. If "energy dump" is to be accepted as truth, then he should've killed several opponents by now

actually assuming 100 mph fastball and 5.5 oz = 115 ft.lb.

 

[mavracer]

15 yrs and have never seen an injury from momentum.

unbelievable 15 years and not one car accident

 

[Kentak]

What I'm talking about is the concept that the momentum of a handgun round will physically injure someone, as distinct from the trauma caused by the crushing and tearing from direct projectile contact.

Good grief. What do you think keeps the bullet moving forward to continue to crush, tear, and penetrate? Answer: Momentum.

Suppose it were possible to do a perfectly controlled experiment on the same living subject. Obviously, this has to be hypothetical, but the answer should be obvious.

In the experiment, we will fire a certain bullet that will enter the subject at a specific point and at a specific angle. We then examine the wound and document all injury.

Next, (this is the hypothetical part) we reanimate the subject and heal him. Now we fire an *identical* bullet that enters the subject at the *identical* point and at the *identical* angle as before. Except we have increased the velocity to increase the momentum of the bullet.

Any doubt trial 2 will have more severe trauma?

You can repeat the experiment keeping velocity constant, but increasing the bullet weight to increase the momentum. All other variables being equal, any doubt that a 147 grain 9mm bullet traveling at 1000 fps will cause more injury than a 115 grain 9 mm bullet traveling at 1000 fps?

So, of course momentum is a factor in "stopping" a threat--to the extent that bullet momentum allows a bullet to perform as intended.

It's important to understand that other variables come into play as well. Which will cause more trauma, a slow heavy bullet or a fast lighter bullet that has equal momentum? Despite what the proponents of each camp might claim, there is no hard and fast answer to that question. What clothing is the target wearing? Where does the bullet hit? What kind of tissue and what anatomical structures are in the bullet's path?

As I said in a previous post, you won't see any injury caused by a bullet with zero momentum.

K

 

[Lone_Gunman]

But, bullets that have more momentum are more likely to cause more serious wounding, all other things being equal.

First, yes I am a physician... a surgeon.

Second, the momentum doesn't directly cause tissue trauma. Momentum increases penetration that causes trauma. I realize a bullet with no momentum will cause no trauma, but it causes no trauma because there is no penetration. Maybe we are playing semantics here, but it sounded like the original poster refered to momentum injuries as being something seperate from the actual penetration injuries, and I took that to mean he was talking about some other wounding technique he thought bullets with a lot of momentum had, kind of like energy of high powered rifle rounds causing tissue trauma that is in excess of the actual penetration.

Third, my comments were about gunshot wounds, not motor vehicle accidents.

The Original Poster refered to momentum injuries as being something seperate from the actual penetration injuries, and I took that to mean he was talking about some other wounding technique he thought bullets with a lot of momentum had.

He had stated: "What I'm talking about is the concept that the momentum of a handgun round will physically injure someone, as distinct from the trauma caused by the crushing and tearing from direct projectile contact."

What does that sentence mean?

 

[critrxdoc]

It just doesn't make sense

I have read the FBI summary and other papers on handun wounding and still am skeptical. It does not make sense that from rationale physics we would deduce that a 9mm and (.355) a .357sig (both 9mm bullets) can have the same mass, same penetration and the 9mm has ballistics : 115gr @ 1415fps / 511ft. lbs, and the sig has ballistics : 1550fps / 614 ft. lbs, that 100 FPE is just going to vanish into thin air. Or an even better example the .357mag at 125gr @ 1700 fps / 802 ft lbs. Are we going to say that now 300FPE energy is going to evaporate given equivalent penetration and expansion? Do we then assume that given equal placement and penetration that a .357mag is no better than a 9mm? I vehemently disagree!

The laws of physics don't change! Humans are not like terminator 2 in which projectiles are absorbed into a liquid matrix. Temporary cavities cause injury in ways that we may not understand completely, but we cannot dismiss them because of our ignorance.

 

[Lone_Gunman]

The higher velocities of the 357 sig and 357 magnum result in more violent expansion of the projectiles. This causes more tissue trauma. I do not believe the small amount of additional energy the 357 sig has directly contributes to its wounding ability, other than by increasing bullet expansion and permanent cavity.

At some point, additional injury does contribute to wounding. This is seen with high powered rifles, where velocities are much much higher.

 

[Kentak]

Ok, Doc, thanks for clarifying.

No disrespect for the work you do as a surgeon intended. But, your comment about momentum not causing injury really had me wondering what you meant.

Obviously, a bullet must penetrate in order to reach and cause enough damage to the CNS or circulatory structures needed to convince an attacker to stop.

Let me make a point about momentum and penetration and I would welcome your comment.

I assume you would agree that if I had a 9 mm diameter steel rod with a tip similar to a bullet, I could, given a way to get a firm grip, thrust it into the thoracic area to a depth of, let's say, 8 inches. Would you, as a surgeon, agree that the nature of the wounding caused by that rod would be less severe than that of a 9 mm bullet that had enough momentum to penetrate the same area the same 8 inches? As I see it, the rod would tend to *pierce* tissue and structures. Maybe even crack a bone. But, wouldn't a bullet, following the same path, do more damage? First, there would be the trauma of a temporary wound cavity that would not exist with the rod. Also, wouldn't the bullet cause more tearing and ripping (and, thus, bleeding), rather than piercing? Finally, wouldn't the bullet hitting bone, due to the physics of momentum transfer, be able to shatter bone and cause secondary fragments?

My point in all this relates to the OP's contention that it's penetration alone and not momentum that is the agent of wounding. I'm maintaining that the momentum of the bullet is also important, not only to ensure adequate penetration, but to contribute to the wounding as described above.

Is my point valid?

K

 

[Kentak]

critrxdoc,

I agree with you completely. Basic physics. Energy is the ability to do work. Work, like in violently moving tissue, tearing, ripping, shattering, fragmenting, all that good "sheet." Energy dump is not a meaningless concept.

Remember when Reagan was shot with a .22 handgun? It caused a very serious wound because it penetrated. It penetrated even though it was a relatively low energy round because the bullet did not fragment and had a small cross-section to offer less resistance to penetration.

Now, if Reagan had been shot in an identical manner, but with a .223 (same .22 diameter) having much greater energy, does anyone think that additional energy won't have an effect? Darn right it will. First, some of that energy will likely go into fragmenting the bullet, and each fragment will have enough energy to continue to wound and penetrate. Perhaps the bullet will hit a rib and splinter it, shredding lung tissue or blood vessels. More energy means more slicing and dicing, folks.

K

 

[WinchesterAA]

What kills is breaking things inside of a living creature.

A well placed shot will take anything down with anything, but you could nail someone with a .50 and just miss the heart by milimeters and they'll be up and running in a couple of months.

Provided they don't get shot again, that is.. Hence the key -

anything worth shooting is worth shooting twice (or more).

 

[antsi]

Kentac,

I think there are two different questions here.

1) does momentum or energy have anything to do with wounding from firearm projectiles? To this question, the obvious answer is "yes." Energy is what gives the projectile the ability to do work. Moving it through the air, penetrating tissue, fragmenting or expanding the projectile itself, crushing or cutting tissue - these are all different kinds of physical work and all require energy to make them happen.

2) Does energy or momentum make any additional contribution to wounding, above and beyond the physical work that is done? I don't think there is any proof of this at handgun velocities.

 

[turtlehitman]

Energy transfer

First I would like to say that I agree that "knock down" power is very misused.

I have used the term "energy transfer", I think they are not the same. IMO energy transfer is simply the target absorbing energy from the bullet. it takes energy to do damage. logicly the more energy the more damage(to a degree).

the bullet transfers energy into organs which they absorb. thereby damaging them. thats what stops the threat.

thats how I think of "energy transfer"

 

[Soybomb]

it sounds to me as though you are postulating penetration to be independent from the kentetic energy of the projectile. Does it not take energy to break the bonds of the tissue, and bones on its way to the "large, blood bearing organs"?

What modern terminal ballistics say with regards to that is that kinetic energy itself does not indicate how well a bullet will stop a person. We need to examine the type of wound the bullet can create with that energy, beause the wound is the end result we're interested in. We're wanting a bunch of tissue damage, not to win a dungeons and dragons numbers game.

Any yes the idea of energy dump/energy transfer as playing a significant role in handgun wounding is generally considered hogwash today and instead we realize there is no magic to it, you need to destory the important parts of the body to break it and force it to stop. Some people still believe it, but thats nothing new..

 

[Kentak]

Any yes the idea of energy dump/energy transfer as playing a significant role in handgun wounding is generally considered hogwash today and instead we realize there is no magic to it, you need to destory the important parts of the body to break it and force it to stop.

Energy transfer is hogwash? Please explain to me how you "...destroy the important parts of the body to break it..." *without* transferring energy from the bullet to those parts.

This is high school physics, people. Not magic at all.

Let's explain this in street physics. You're playing pool and want to really scatter the balls after the rack up. The numbered balls represent tissue, blood vessels, organs, and bones. The cue ball represents the bullet.

Assuming you aim for the same point on the racked balls, are you going to hit is softly (low energy) or hard (high energy)? Why?

Ever hit the point ball dead on and see the cue ball just about stop in place? What happened to all the momentum that cue ball had? Did it evaporate? Nope, every bit of it *transferred* to the racked balls and set them in motion. If those balls were body parts, they would move, tear, break, etc. And, the harder you hit that cue ball, the more energy is transferred to the balls and the more they move.

That's an energy dump. Now, what happens if you hit the racked balls with a glancing blow so that the cue ball is just deflected and goes on to smack a rail? The balls don't move as much. Why not? The cue ball didn't "dump" all it's energy into the balls, but retained some and carried it to the rail instead.

A bullet that does not dump all it's energy into the target is letting some of the energy escape to do work elsewhere.

K

 

[Kentak]

2) Does energy or momentum make any additional contribution to wounding, above and beyond the physical work that is done? I don't think there is any proof of this at handgun velocities.

I don't know of anyone who is claiming that. Certainly I am not. Every bit of physical work done in the target is due to the energy brought into it by the bullet's momentum. Yes, bone fragments can cause their own wounding, but only from the momentum transfered to the fragments by the bullet.

K

 

[tkendrick]

A well placed shot will take anything down with anything, but you could nail someone with a .50 and just miss the heart by milimeters and they'll be up and running in a couple of months.

I don't want be insulting, but this is nonsense.:banghead:

Don't generally like to get too graphic, but.....

A solid hit in the upper chest cavity at three hundred yards with a fifty BMG will generally create an exit wound 12 or more inches in diameter, and will pretty much turn the heart and lungs into pate and then spread them, along with bone fragments, meat and blood all over country side behind that target. That, with a FMJ bullet.

Following much of the penetration arguement I'm seeing here, you would expect to see a simple half inch hole drilled through that body.

May sound good in theory, but I can tell you from personal experience, it just aint so.