Needed Energy for killing.... is it a myth??

Let me elaborate.

If you throw a bullet at a deer, you may raise a welt, but highly unlikely to kill it!

Bullets make larger than bullet diameter holes by going VERY fast. A SLOW bullet is no better than a field point arrow! Unless you have a "magic" bullet that can determine the amount of energy that it will expend traveling through an animal, then it may exit, or it may not on a long shot where you are taking a risk on crippling an animal.

IMO, if I have a choice between a bullet that makes a 2 inch entrance wound, and a 1 inch exit wound and continues on at 1000 fps.
OR
A 3 inch entrance wound followed by 12 inches of penetration with the bullet left inside the animal, I will take the exit wound EVERY SINGLE TIME!

Just one more thing, a 200 grain bullet that stops inside of an animal is STOPPED! It is not doing anything to the animal in the way of damage...

edge.
 
Many Doctors have seen more gunshot victoms than a thermodynamicist have and without the proper technical training make assumptions that are incorrect. Kinetic Energy is not conserved and is transfered as heat. it is direct force of projectile collision that casuse the wound channel and it is the pre concieved miss understanding of the differences between kinetic energy and direct force and the oversimplification of useing kinetic energy as a ballistic model that is the down fall of such use.

Example in my 4" M-57 I can shoot a 230 grain flat point hard cast bullet at 1338 FPS that equals 914 FPE. My 500 JRH shooting a reduced load behind a 440 grain flat point hard cast bullet at 950 FPS equals 882 FPE.. The wound channel created by the 440 grain 50 Cal. bullet creates a large diameter wound channel because of a greater amount of direct applied force even though it has less FPE. The 440 grain also out pentrates the 230 grain 41 Cal. bullet as well

Similarly, someone who knows alot about energy and little to nothing about gunshot wounds in living tissue as well as anatomy, physiology and a plethora of other fields, can draw incorrect conclusions due to their lack of technical knowledge in those areas. Difference is, MD's have to go through a minimum of two semesters of college physics, an engineering student doesn't have to go through A&P, Cellular Biology, Molecular biology etc.
Of course Kinetic energy is not conserved, it rarely is, but total energy is always conserved. Now the difference between the kinetic energy of a bullet when it entered the system (body) and when it exited was in fact imparted to the system. Some of it will undoubtedly be trasformed to frictional heat between the bullet and the medium, however I don't imagine a great proportion of it is, alot of the energy of the bullet has to do work (kinetic energy) now that work energy may eventually transform into heat, elastic and potential energy. But it's going to do work first. That work may not be directly proportional to the energy imparted to the system but it will be proportional. As to whether trauma increases in a quantum or graded way is a different ball of wax, But at some level, more energy imparted to the system is going to cause more trauma.

As for your examples, muzzle energy has nothing to do with it, and hard cast bullets are a poor model for a controlled expansion hunting bullet. What matters is energy lost to the system (body), and when talking about a expanding projectile that will loose a great deal of energy as it traverses the body, kinetic energy will be proportional to trauma to some extent.
 
The bullet energy is released and eventually has to stop somewhere. Preferably while it's still in the animal. The placement, the construction of the bullet and the velocity play very big part in the killing department. The same bullet, the more velocity, the more energy, the bigger the internal damage, the better the kill.
Don't believe me? So compare how spectacular are your effective kills at 100yards and not so at 1000yards with the same hit/bullet. The internal damage at 100yards is much more than the damage at 1000yards.
If your ***** a heart with a 1/4" screwdriver it will eventually kill without a doubt, but not as quickly as with a bullet at 3000fps.

Peter


Energy.jpg
MacPhearson.jpg
 
jwp475, IMO, taking a picture of a page without commentary adds little. Posting it twice does not add to its value!

You posted two complete pages with nothing more. Is there commentary to go with them?

While someone could say that energy in ft/lbs is not applicable, but it IS a description of the projectile. If I tell you that a 150 grain bullet has 4,000 ft/lbs of energy then you know its velocity! I did not tell you the cross section, so the data is incomplete, not wrong in any way.

edge.
 
The book is by Duncan Mcphearson titled "Bullet penetration Modeling the Incapacitation Resulting from Wound Trauma".
He explains that only someone without Thermodyanmics training would attempt to relate energy as the determining factor in Wound Trauma Incapacitation. He farther explains that the dynamic variable in collisions that is conserved is momentum; kinetic energy is not only not conservedinreal collisions, but is transfered into thermal energy in a way that but usually cannot be practicaly modeled. The energy in collisions can be traced, but usually only by sliving the dynamics by other means and then determining the enrgy flow.
 
Well I've done some research on Mr. McPhearson in the last couple days and though I'm sure he's a very accomplished engineer. His credentials as a ballistician consist of being consulted by conspiracy theorists about the JFK assasination, and publishing the book you have so generously promoted as the end all discussion on terminal ballistics. Unfortuneatly, he has not published one single scientifically reviewed journal article on the subject of ballistics. He is apparently more than happy to make money on his "expertise" in the field, as long as his claims are not subjected to the scrutiny of his peers in the scientific community. I think that about sums it up.
 
Well I've done some research on Mr. McPhearson in the last couple days and though I'm sure he's a very accomplished engineer. His credentials as a ballistician consist of being consulted by conspiracy theorists about the JFK assasination, and publishing the book you have so generously promoted as the end all discussion on terminal ballistics. Unfortuneatly, he has not published one single scientifically reviewed journal article on the subject of ballistics. He is apparently more than happy to make money on his "expertise" in the field, as long as his claims are not subjected to the scrutiny of his peers in the scientific community. I think that about sums it up.

Apparently Dr. Martin Fackler is fairly impressed by Mr. MacPhearsons work as indicated by his review of MacPhearsons book


Review of Bullet Penetration by Dr. Martin Fackler


This review, written by Martin L. Fackler, MD, appeared in the January 1995 issue of Fighting Firearms and is reproduced with the kind permission of the International Wound Ballistics Association.

This remarkable book by Duncan MacPherson advances wound ballistics to the status of a mature predictive science. One must consider the normally slow growth evidenced in the history of scientific methods and ideas to appreciate the significance of this achievement. We have had a valid tissue simulant with which to do bullet testing that is applicable quantitatively to the human body for only a dozen years: for only half that time has this tissue simulant been used widely in a way that gives comparable results ("BB" penetration calibration of each block).

Bullet Penetration unveils MacPherson's unique mathematical predictive bullet penetration model which he derived from the general equations of motion. He used the methodology described above for experimental shots with various projectiles into calibrated 10% gelatin to validate his model and determine its empirical constants.

Several years ago, when Duncan MacPherson tried to explain to me the necessity for a mathematical bullet penetration model, I didn't understand why it was needed or how it might be applied. If I had any question about the effectiveness of a new bullet I would just shoot it into 10% gelatin and measure the results. I didn't even have to do gelatin shots to answer most of the questions I was asked about bullet performance. I could usually make a pretty accurate estimate by mentally comparing the bullet in question with the results of the several thousand bullets I had already tested. Finally, after MacPherson's experimental verification of his model was nearly finished, it dawned upon me that his predictive penetration model does essentially the same thing as my experience based estimates did -only his model does it more accurately and it can be applied to a far wider variety of questions. It puts the equivalent of more than a decade of systematic bullet testing experience at the fingertips of any intelligent reader who is willing to think the model through.

MacPherson derived his model using the rigorous mathematics and physics required for scientific accuracy: this derivation is included in a 35 page chapter that will satisfy the most critical mathematically oriented reader. MacPherson's writing style and vocabulary, however, make the basic principles and results understandable to the layman.

MacPherson has included an outline of the contents of his book's chapters in the introduction, as well as providing an excellent summary at the end of each chapter. He exposes and corrects common fallacies -- such as the presumption that kinetic energy determines bullet effect. In that section we find:

Newton's laws of motion describe forces and momentum transfer, not energy relationships
Damage is done by stress (force), not energy.
Stresses cause damage only if they strain body tissues above their elastic limits. Most expanding handgun bullets simply waste the kinetic energy used in producing the small temporary cavities they cause.
Included is an excellent clarification of statistics for the layman. It explains how the seemingly plausible collection of data from shootings is immensely compounded by the large number of variables; that any claim that incapacitation from bullet hits can be assessed within a few percent based on shooting data "is based on ignorance, or fraud, or both." This easy to understand primer on statistics should enable the layman to avoid being misled by data that is "too good to be true."
Although MacPherson derives his penetration model with the rigor necessary to satisfy the most critical professional scientist. he also provides graphs derived from the model to enable the interested layman to apply the information easily. For example, his model permits the interested reader to obtain the maximum in accuracy from bullet testing in ordnance gelatin. Calibrating each gelatin block with a "BB" shot (at 590 ft/s) gives a quality control check, but within the calibration standards (+/- 1 centimeter of the 8.5 cm standard penetration depth) there can be a variation of +/- 12% (and many laboratories are reporting shots in which the BB penetration does not meet these standards). From MacPherson's graphs the reader can obtain the adjustments to normalize results to the standard 8.5 cm even if the calibration shot was several cm from the 8.5 cm standard. This normalization of experimental results cuts out a large source of potential error, that has heretofore been overlooked, and allows more accurate bullet performance comparisons.

MacPherson includes graphs that allow the reader to obtain a realistic approximation of bullet penetration in gelatin from bullets recovered from shots into water. The expanded bullet's diameter, weight, caliber, and velocity, plotted on the appropriate graph, allows the reader to read off the equivalent penetration depth in 10% standard gelatin (calibrated to a "BB penetration depth of 8.5 cm.)

The photographs relating striking velocity to deformation and expansion for various cast lead projectiles and jacketed expanding handgun bullets should prove exceptionally useful to those who experiment with, or are interested in, bullet
design -- or are just interested in understanding better what they have seen in their own experimental work or that of others.

MacPherson's credentials are impressive to say the least -- he is, in fact (no joke), a rocket scientist -- whose accomplishments include developing a new guidance technique and the equations that were used to guide the Mercury astronauts into orbit. He is now a busy consultant in space flight with an impressive clientele. Duncan has had a lifelong interest in firearms as a shooter and experimenter and has read widely in the field. He demonstrated the depth of his insights into bullet effects when, in 1976, he published "Relative Incapacitation BULListics." That article analyzed and pointed out the fatal flaws in the now infamous Relative Incapacitation Index (RII). The National Institute of Justice NIJ, originator of this ill-fated bullet rating scheme, disregarded MacPherson's well-founded criticisms. in 1986, two FBI agents had to die, unnecessarily, (in the Miami shootout) to prove to the world that MacPherson was entirely correct when he pointed out, ten years previously, that the RII was seriously flawed.

The strongest focus of MacPherson's work is on getting the maximum efficiency out of the inherently limited handgun. He discusses accuracy, recoil, calibers. bullet types, bullet velocities and bullet weights; relating all of these to his wound trauma incapacitation model (which is his penetration model with human anatomy, physiology and psychology and other considerations added).

This superb book can provide those responsible for weapon and bullet selection with the reliable information they need to make informed choices -- to balance intelligently the inevitable pros and cons that accompany these compromises. It further provides data and insights that are of crucial importance to Wound Ballistics Researchers, Forensic Pathologists. Firearms Examiners, Trauma Surgeons, Ordnance Engineers, Law Enforcement Personnel and others critically dependent on firearm performance.

MacPherson's book is a scholarly scientific work. It is not for those who prefer their facts predigested and spoon fed -- it is for mature minds that are willing and able to think for themselves. Rather than just doling out answers, MacPherson gives his readers the tools they need to figure out the best answers to their own particular bullet-effect-related problems for themselves.

Martin L. Fackler, MD
 
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OK, the last line is important!

" Rather than just doling out answers, MacPherson gives his readers the tools they need to figure out the best answers to their own particular bullet-effect-related problems for themselves.

Martin L. Fackler, MD"

SO, WHAT ARE YOUR CONCLUSIONS?

All you are doing is quoting someone without relating why it is relevant to this PARTICULAR discussion!

Since you insist on quoting, I will glean this from your post:

"The strongest focus of MacPherson's work is on getting the maximum efficiency out of the inherently limited handgun."

While some of us are indeed handgun hunters, I feel the majority are rifle hunters!
Please explain the ins and outs of these previous pages with respect to the rifle shooters versus the handgun hunter.

edge.
 
Now your qouting sales pitches from gun rags? Come on! I'm not going to do your work for you and research Dr. Fackler. But seriously, there are umpteen million "MD's" touting the curing magic of magnetic bracelets on network T.V. too. That does not mean that there is any substance to their claims. I'm sure there is some substance to McPhearsons book, but many of his postulates have been disproved especially relating to ballistic waves and many others. I'm sure he is a bright man, but just cause his book (published 14yrs ago) says something is true doesn't mean it is. There is a big difference between BB's (non deforming, stable projectile) in ballistic gelatin and hunting bullets smacking animals. If you'd care to research beyond McPhearson's book you may find that many of his theories have been disproven. Out
 
Martin Fackler, a surgeon in the Vietnam ear later became head of the Army Wound Ballistics. Today Martin Fackler is President of the "International Wound Ballistic Association"
I would hardly call him another "Bullet Salesman" or "Gun Rag Pitch Man"

The reason that I posted the book page and other realevant info is to explain from a technical point why FPE (kinetic enregy) is meaninglessin opredicting the Wounding abilty of different calibers and or cartridges.

Martin Fackler has stated for years that FPE is not realivent. Newtons laws of motion do apply. These laws are of mass and momentum.
The wound is a direct cause of direct applied force, not FPE (kinetic energy). Most people believe that they are one and the same, but they are not. I posted pictures of an exit hole from a 300 win mag with 2700 FPE and a picture of an exit in the same Elks rib cage created by a 500 JRH with ony 882 FPE that is about 3 times larger than the one created by 2700 FPE.

Another example of direct applied force (which is not the same as kinetic energy) is my 41 mag shooting a 230 grian flat point hard cast bullet at 1338 FPS (chrono'ed) producing 914 FPE, compaired with the 500 JRH shooting a 440 grain flat point hard cast bullet 950 FPS resulting in 882 FPE. The advantage in FPE is with the 41mag, yet the 500 produces a larger diameter wound and out penetrates the 41 EVERY TIME. Why, because the area of direct applied force is greater with the larger diameter projectile and it also has the most momentum for more penetration.
 
Now your qouting sales pitches from gun rags? Come on! I'm not going to do your work for you and research Dr. Fackler. But seriously, there are umpteen million "MD's" touting the curing magic of magnetic bracelets on network T.V. too. That does not mean that there is any substance to their claims. I'm sure there is some substance to McPhearsons book, but many of his postulates have been disproved especially relating to ballistic waves and many others. I'm sure he is a bright man, but just cause his book (published 14yrs ago) says something is true doesn't mean it is. There is a big difference between BB's (non deforming, stable projectile) in ballistic gelatin and hunting bullets smacking animals. If you'd care to research beyond McPhearson's book you may find that many of his theories have been disproven. Out



MacPhearson's work has not been proven false in way and the laws of physics do not change over time. MacPhearson Ballistc Model covers (as far as I can deteremine) every bullet shape possable including expand bullets.
 
A funny thing about this subject is that folks get set in their ways and won't listen to other ideas!

If energy is not important, then take your 500 JRH and hit a deer with it with an energy of 40 ft/lbs!

You might argue that that is ridiculous, but energy is not important, remember :)
That same 40 ft/lbs will cleanly take a deer with a well sharpened broadhead!

IMO, there is some truth to most arguments!

One needs to take the bullet construction and cross section into account! A 45 caliber hard cast with a .35 meplat will crush a path as wide as an expanding bullet of smaller diameter. The bullets construction will dictate how much energy will be required to ablate the point to achieve a blunt shape that destroys tissue at a greater rate. Obviously a monolithic copper bullet will require more energy that a more fragile ballistic tip.

The projectile can't be eliminated in any discussion concerning wounding. To pick a ft/lb number without the corresponding bullet is meaningless, but once you describe the bullet and tell someone the energy, a reasonable decision can be made.

edge.
 
A funny thing about this subject is that folks get set in their ways and won't listen to other ideas!

If energy is not important, then take your 500 JRH and hit a deer with it with an energy of 40 ft/lbs!

You might argue that that is ridiculous, but energy is not important, remember :)
That same 40 ft/lbs will cleanly take a deer with a well sharpened broadhead!

IMO, there is some truth to most arguments!

One needs to take the bullet construction and cross section into account! A 45 caliber hard cast with a .35 meplat will crush a path as wide as an expanding bullet of smaller diameter. The bullets construction will dictate how much energy will be required to ablate the point to achieve a blunt shape that destroys tissue at a greater rate. Obviously a monolithic copper bullet will require more energy that a more fragile ballistic tip.

The projectile can't be eliminated in any discussion concerning wounding. To pick a ft/lb number without the corresponding bullet is meaningless, but once you describe the bullet and tell someone the energy, a reasonable decision can be made.

edge.



Remember that direct applied force and FPE are not tied together and are not the same thing. The simplistic fotmulars of FPE attempt to predict the wound or rate it by FPE and fail to do so accurately. As you mentioned the low amount of FPE possed by an arrow is correct, by one must remember that the arrow contains the ability to apply a high amount af direct applied force, because of its momentum. There is no dought, that with more velocity one can increase the amount of direct applied force. Also as you also stated none of this matters unless the bullet construction is such that it has the ability to apply the force for a significant amount of time and distance (penetrate).
 
If momentum is all there is to have ( p = m * v ) I would always go for the higher velocity aka higher energy calibers...
So a .300RUM with 180gr. would be better by momentum than the .308W with 180gr...

Good that momentum does only work in Hongkong-Shooter-Movies... when the bullet momentum goes over to the bad guy and throws him across the room... looks cool...

The problem with tissue damage is double-edged...
On one side we want tissue damage...
On the other side we want penetration to make tissue damage at vital tissue...

Tissue damage is done by direct contact with the bullet (manly handguns) or by tissue displacement (manly rifles) aka cavitation (in that case the bullet has only minmal contact to the tissue)...

And because Newton is valid both parts of the terminal ballistic has energy in it...
Paired with sectional density we have all the problem and the cure in two formulas:

1. Damage done to tissue aka work W is equal to the energy that is transfered from the bullet to the tissue...
The amount of energy transfered is proportional to the starting energy (energy just before contact) and the sectional density...:
W = Elost ~ E / SD
The work done at any given point is therefore proportional to the SD and the E at the given moment... while E will go down to zero, SD will go down aswell until the bullet finishes expansion... or break-up into smaller parts, each with part of the energy and a very low SD...

2. Penetration is equal to the Energy Denisty which is the following:
Penetration s ~ ED = 1/2 * SD * v²
or if we put in SD = m / A; (A = area) we get:
s ~ ED = 1/2 * m * v² / A = E / A
So while energy goes down again, SD goes down also (A goes up)... put this time it is not good to have a low SD beacuse that shortens the penetration...

And thats the double-edged sword...
If we want damage we need high energy and low SD... aka fast and expanding bullets...
If we want deep penetration we need high energy and high (stable) SD... aka fast non-expanding bullets...

But because we want both we need the right kind of caliber/bullet for the job... one that expands as much as possible in the target and will penetrate the target completely...
While we are always able to max out energy to the bullet - make it faster and heavier - we must chose the right kind of expansion...

Also important to actual killing a being is that it is most convenient when it stays at the shot... best way to do this is to 'punch' the spinal cord hard enough... this can be done with the help of the hydraulic pressures that come from high energy (fast) bullets, aka cavitation...
It is not the most reliable methode (deer in stress is more hardend), but it is the only 'hope' you have when you aim for the vital organs (heart) which are far from the spinal cord and which hit right kill (first is
unconsciousness) in a few seconds...

So the bigger the target the more energy you need to reach the spinal cord with this secondary effects...

Only problem with expansion that is this not preferable solved, is that it would be good to have very low expansion at the beginning and when the bullet is in the center of target expansion goes up fast to have maximum possible damage where it is needed...
Yawing bullets can do this... but are not reliable to do it...

Oh and my preferred experts are Sellier and Kneubuehl...
 
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