Long Range Hunting Online Magazine

Go Back   Long Range Hunting Online Magazine > Hunting > Long Range Hunting & Shooting

Long Range Hunting & Shooting Nightforce Optics


Terminal Energy Required to Kill Game

LinkBack Thread Tools Display Modes
Unread 04-18-2008, 03:55 PM
Platinum Member
Join Date: Feb 2005
Location: USA
Posts: 2,598
Any ballistics formular that uses FPE as a basis to rate Wound Trauma Incapacitation is doomed to failer.
Why you ask? Read the following for the answer

"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
range it,check the wind, dial in correction, aim and only one shot
Reply With Quote

Unread 04-19-2008, 12:18 AM
Junior Member
Join Date: Feb 2005
Location: Westlock
Posts: 22
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
Always did like the fat ones Barrels that is !!
Reply With Quote
Unread 04-19-2008, 01:12 AM
Silver Member
Join Date: Feb 2006
Location: Pueblo, CO
Posts: 286
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.
Reply With Quote
Unread 04-19-2008, 11:35 AM
Platinum Member
Join Date: Jul 2004
Location: Texas
Posts: 7,231
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

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
Reply With Quote
Unread 04-19-2008, 11:48 AM
Platinum Member
Join Date: Feb 2005
Location: USA
Posts: 2,598
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..
range it,check the wind, dial in correction, aim and only one shot
Reply With Quote
Unread 04-19-2008, 12:19 PM
Silver Member
Join Date: Feb 2006
Location: Pueblo, CO
Posts: 286
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)

Last edited by devildoc; 04-19-2008 at 12:28 PM.
Reply With Quote
Unread 04-19-2008, 12:57 PM
Platinum Member
Join Date: Feb 2005
Location: USA
Posts: 2,598
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
range it,check the wind, dial in correction, aim and only one shot
Reply With Quote


Thread Tools
Display Modes

Similar Threads for: Terminal Energy Required to Kill Game
Thread Thread Starter Forum Replies Last Post
How much Energy to kill a Deer? 700man Long Range Hunting & Shooting 35 07-18-2013 03:30 PM
Trying to find min amount of bullet energy required to make clean kill at long range Thewildedge Long Range Hunting & Shooting 8 01-02-2011 06:40 AM
Terminal results from 350gr SMK on game. groper Rifles, Bullets, Barrels & Ballistics 10 08-26-2010 08:15 PM
lower velocity/energy limit MK performance on big game sscoyote Rifles, Bullets, Barrels & Ballistics 4 07-13-2003 08:29 PM
Terminal Energy is.....? MAELTY The Basics, Starting Out 4 03-25-2003 08:02 AM

All times are GMT -5. The time now is 12:48 PM.

All content ©2010-2015 Long Range Hunting, LLC