# Terminal Energy Required to Kill Game

#### jwp475

##### Well-Known Member
Any ballistics formular that uses FPE as a basis to rate Wound Trauma Incapacitation is doomed to failer.

"The first law of Thermodynamics requires conservation of total energy in any collision, but this information is not useful in analysis of the collision because there is no direct way to determine what fraction of the kinetic energy is transformed into other forms of energy (usually most of this is heat or thermal energy)"

"Foot pounds is the Unit typicaly used in ballistics and many other dynamics problems. The British Thermal Unit (BTU) is often used for "heat energy"; one BTU equals approximately 778.1 foot pounds. Joule is the unit of energy in metric (or standard international) units' one joule is equal to one newton meter or one watt secound, and equals approximately 0.73756 foot pounds."

The above quotes are by Duncan MacPhearson and are technicaly and scientificaly correct....

Kinetic energy absorption (the process of the transformation of kinetic energy into thermal energy does not equate to tissue damage in many physical processess...

Newton's laws of motion describe forces and monemtum transfers not energy relationships.. The dynamic variable that is conserved in collisions is momentum; kinetic energy is not only not conserved in real colisions but is transformed into thermal energy....

If anyone can disprove these basic laws of science, then a Pultzer Prize in Science is a cinch

#### fenceline

##### Member
shot placement

you could probbly kill any animal on the planet with a 22lr an indian lady in Slave Lake kill one of the largest GRIZZELY bears ever shot with a 22 not advisable but doable

#### devildoc

##### Well-Known Member
Didn't we already have this discussion? You can also chop down a redwood with a pocketknife, but I wouldn't try it. Kinetic energy may not be a 1:1 relationship as far as it's lethality per unit mass. But it is proportional, and if you disagree, you can go hunting for cape buffalo with a .22 or any other cartridge that puts out low FPE and I'll interogate the toe jam that's left about how your opinions may have changed. There are too many variables to make directly proportional relationships when it comes to terminal effect, but the amount of energy a properly chosen hunting bullet has will in fact have a proportional relationship to it's lethality. Key words here are "properly chosen" and "hunting bullet", As in you've chosen a bullet that will expand well, yet retain mass well and penetrate adequately. If you're shooting a steel BB that will not deform, overpenetrate and not transfer it's energy, this doesn't apply (as well as FMJ). Likewise, if you push a frangible projectile to where it dumps its energy without penetrating vitals this will also not apply. But provided that you choose a suitable projectile for the game and velocity you are operating with, it does....end of story.

#### J E Custom

##### Well-Known Member
Well said Devildoc

This issue will never be settled because of so many variables in hunting.

I have experienced many different results using the same bullet an rifle
combination on the same type of animal with bullet placement being in
the same general location (Heart/Lung)and learned the hard way that
shot placement for the type of bullet and energy at POC makes all the
difference.

Energy does one no good if it is not transfered to the game, EXAMPLE=
One time I went hunting elk with a 30/378 using 200gr noz partitions
this had allways been a real stopper,until this hunt.

I called this very large bull in within 150yrds broad side and let him have
one in the boiler works, He did not even flinch and just stood there.

Talk about spooky Now I'm thinking ,well I realy blew that and started
loading the the second round.once I placed the crosshairs where I would
place the next round I spotted a tiny hole with blood around it and decided
not to shoot again as long as he stood there.

And in a few minutes he just went down. And after skinning him I found out
that the bullet had missed the ribs on both sides and went completly through
with out expanding. Thus the reason for him standing there not knowing what
happened.Had he ran he could have gone hundreds of yards and maybe not
have been found because there would have been no blood trail.

Had I been using an accubond or balistic tip instead the results would have
been totaly different on this shot.

This changed the way I think about shot placement just before I shoot each
time. Now I try to deliver all the energy to the animal possible with the bullet
i'm using at the time with shot placement based on the distance and the position
of the game at the time.

As I found out All the the theory in the world did'nt help and whats realy
important is "where the rubber meets the road".

Energy is only one of the equations but it is a very important one if you dont
want to lose the game your hunting or end up the green stuff between an
elephants toes as someone mentioned, I believe that to much energy is better
than not enough.

Just my 2 cents
J E CUSTOM

#### jwp475

##### Well-Known Member
Kinetic energy is not transfered to the tissue MOMENTUN is. Kinetic Energy is transfered into other forms of energy mostly THERMAL. Momentum is conserved in collisions and is transfered and their is also Hyrauliuc pressure to consider as well and the higher the velocity the more of a role Hudraulic pressure plays

Newtons Laws Of Motion deal wwith Momentum transfers and not energy relationships.

All collison equations figure kinetic Energy in Joules (the metric measurement of heat (thermal energy) Momentum is conserved in Real Collisions and is transfered..

#### devildoc

##### Well-Known Member
So, let me ask you a question there jwp,....are Momentum and kinetic energy proportional? (I'll help you out, momentum=mv; Ke= 1/2mv^2)

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#### jwp475

##### Well-Known Member
No need to help me out with out the kinetic energy there would b e no force for acceleration, but kinetic energy is not what is transferred to the tissue, momentum is. Why is this important? Example I have a 230 grain flat point hard cast bullet that achieves 1338 FPS out of my 4" M-57 for 914 FPE. I have a 440 grain flat point hard cast that achieve 950 FPS out of my 500 JRH that makes 882 FPE. Judging by the FPE would would assume that the 41 has the edge and would also assume that the wound channels would be larger for the 41 since it has more energy, right. No the larger wound is inflicted by the 500 as well as the most penetration. Why, because the 500 has the edge in the area of direct applied force as well as momentum...That is one of the reasons that predicting the wounding effects of a cartridge using kinetic energy is flawed. If one is comparing the same calibers with equal projectiles and the velocity is increased therefore producing more FPE then yes FPE will rank the wounding effect in the proper order

#### devildoc

##### Well-Known Member
I think you're a little confused, Ke IS transferred, it is not however conserved, however, momentum is. I doubt seriously that anywhere in your book McPhearson states that Ke is not transferred. It must be due to conservation of total energy, the question is what type of energy is it transformed into. And once again, The fact that stuff got moved around during impact is proof positive that at least some that initial Ke was transferred to the tissue as Ke.
Once again, you're comparing apples to oranges, I'm not talking about hard cast bullets, FMJ, Frange, tracer or anything else. Just well designed, controlled expansion hunting bullets. This is part of the problem with trying to apply McPhearson's work on handgun wounds, where he is dealing with a wide variety of bullet constructions and wound sites to hunting where we are talking about bullets designed to expand and penetrate well on a big game animal where we are almost exclusively taking the boiler room, high shoulder or neck shots.

#### jwp475

##### Well-Known Member
You are in correct, if you believe that Kinetic Energy is transferred in a matter that causes tissue damage. It is the transfer of momentum to the tissue as well as hydraulic pressure and this what the mechanism that hurls the tissue away..

Yes in Macphearsons book he states the first law of Thermal dynamics
which is;

The first law of Thermodynamics requires conservation of total energy in any collision, but this information is not useful in analysis of the collision because there is no direct way to determine what fraction of the kinetic energy is transformed into other forms of energy (usually most of this is heat or thermal energy)

The high velocity rifle projectiles do add another dynamic to the wounding process, yet Newtons Laws Of Motion still apply and are scientifically valid and have not been proven wrong since Newton stated them in the 1700's

#### WildcatB

##### Well-Known Member
JWP475 he's not wrong. If Momentum is transferring, so is Kinetic Energy. You can't have one without the other and there is a positive relationship between them. That means that as one grows so does the other.

Here are the equations:
Momentum = Mass x Velocity
Kinetic Energy = (1/2)Mass x Velocity^2

Notice that you can't have one without the other. Each is defined in terms of the same variables - Mass and Velocity.

When the author of your book said that energy is not a factor in a kill, something got lost in translation. I'm sure he meant to say that energy is not the ONLY factor in a kill.

There are many variables that go into a kill - too many to actually quantify in an absolute way.However, to say that energy in NOT a factor in a kill is just as wrong as saying that energy is the ONLY factor in a kill.

Yes in an inelastic collision, it is said that kinetic energy is not conserved because SOME of the energy is converted to internal energy in one or more of the bodies. The important word in that sentence is SOME. That means NOT ALL. You’ve miss-read your book by thinking that ALL or even MOST of the kinetic energy from a bullet is converted into thermal energy. If that were the case, there would be no energy left to be provide momentum. Because even though kinetic energy is not conserved as kinetic energy, total energy is.

#### jwp475

##### Well-Known Member
The first law of Thermal dynamics requires conservation of energy in real collisions.. Kinetic energy is not conserved in real collisions it is transferred into other forms of energy mostly thermal. Ask any Physics Professor...
Kinetic energy is important for sure. Kinetic Energy is the required force that accelerates the projectile (mass).. Remember Newtons 3 Laws Of Motion which deal with Mass, Momentum acceleration, Not Energy relationships

The equations dealing with collisions calculate Energy in Jouls and Joules is the international unit of thermal energy .73756 joules equal 1 foot pound of energy or 1 Newton Meter.. 1 BTU ( Britsh Thermal Unit) is equal to approximately 778.1 Foot Pounds of Energy

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#### jwp475

##### Well-Known Member
One shot complete pass through and the Bull went no where less FPE than a 243, yet much better penetration and tissue damage

The next 2 photos are of the same Elks rib cage

This one is the exit of a 180 grain from a 300 Win with an impact velocity of approx. 2600 FPS for 2700 FPE

This one is the exit of my 500 JRH with a 440 grain at 950 FPS for 882 FPE

FPE doesn't look very accurate to me.....

#### WildcatB

##### Well-Known Member
Kinetic energy is not conserved in real collisions it is transferred into other forms of energy mostly thermal.
This is not the case. While KE is not conserved, I have yet to find a physics book that says it's converted mostly into thermal energy. However, I have read where most of it's converted into damage to the colliding bodies. I'm not a physics professor but I work next to one as a adjunct math instructor. I'll ask Dr. Hannigton the next time I run into him.

JWP475 it's clear you are not reading the replies in this thread (and others) or the book you reference very closely. I suspect that this will continue.

Also,just because energy is defined in Joules doesn't mean the transfer is to thermal energy.

#### jwp475

##### Well-Known Member
No I have reasearched this very thorughly and in Collisions FPE is not conserved. Accept it or not it matters not to me, but it is the case...

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