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

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Unread 04-11-2008, 01:20 PM
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Originally Posted by jwp475 View Post
Yes the terminology is correct, most people have a hard time accepting that fact (I did) because this is not the terminolgy that were grow with (reading in gun magazines). Along with the direct applied force comes hydraulic pressure often miss named as "hydro static shock". This book deals with handgun rounds (velocity levels) as there are other dynamics in volved with velocities above 2000 FPS. Another fact that you are ignoring is that "kinetic energy is not conserved and is transfered as heat". The direct applied force is often "mistakenly refered to as FPE".
I'm certainly not ignoring that Kinetic energy is not strictly conserved. In real world phenomenon no type of energy is Strictly conserved. When talking about physics you have to define your frame of reference. In this case we're discussing the energy transfer from the time an expanding, high velocity bullet (>2000fps) enters an animal to the time it exits. I'm no physicist but I have taken a full year (2 semesters) of algebra based physics. And in the instance we're talking about the only way that any of the energy is going to be directly transformed to heat is through friction. I believe that that frictional energy loss is probably nominal. Now alot of that energy will eventually be transformed into heat. The question is what forms of energy/work it does before it is lost to heat. That would likely be ballistic wave/hydraulic effect, which is; mass in motion; which is.......kinetic energy.
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Unread 04-11-2008, 07:16 PM
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Kinetic enregy is indeed mass in motion, no diagreement here. Dr. Fackler (one of "the" if not "the" leading authority in the world on wound ballistics) states that "kinetic energy is meaningless in determining wound trauma incapacitation". Duncan MacPhearson (One of the top Engineers in the world) states that "energy is not conserved in real collisions, but is transfered into thermal energy in a way that cannot be practicaly modeled. "The first law of thermodymamics 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)".
range it,check the wind, dial in correction, aim and only one shot
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Unread 04-12-2008, 12:34 AM
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Foot Pound is the unit used in ballistics and many other dynamics problems. The British Thermal Unit (BTU) is often used for "heat energy"; one BTU equals approxamately 778.1 foot pounds. Joule is the unit of energy in metric (or standard internationsl) units' one joule is equal to one newton meter or one watt secound and equals approximately 0.73756 foot pounds..
range it,check the wind, dial in correction, aim and only one shot
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Unread 04-12-2008, 02:17 AM
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Guy's, Your knowledge of external and terminal ballistics is impressive,to say the least!
All I know is I had a relative that fed his family of six, venison, for a couple of years when he was injured and couldn't work. He used a .22lr at night with a spot light, he was a dead shot never using more than one round. I know this was not right nor legal, but he had hungry children at home. I don't know how many deer he harvested this way, but it had to be a good number of them.
Also heard stories from a game warden of bull elk being poached with the lowly rimfire.
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Unread 04-12-2008, 04:17 AM
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Heat and energy in bullets...
A pot of coffe has 2.000.000 Joule...!!! My .338 only has 7.000 Joule...:(
Think of that... someone spill coffee over you and you get a wound channel 250 times bigger than the .338 would do...:eek:

Thermal energy is only one form of energy...

The difference between coffee and the .338 is that one is boiling the other is moving...

The form we are most interested in is mechanical energy...
1 Joule is equal to lifting 0,1 kg up 1m
1 pound up 9 inch...
There is no temperature change when lifting up something... beside sweating ofcourse... but thats a other system...

We want to get the tissue moving, not boiling... for the last we would need alot more energy... think of the last time you put something on the grill...
a few thousand Joules to kill it... a few billions to warm it up...

The system that conserves all energy in a deer/bullet-event is pretty big...
it is not the internal of the deer only... something will leave the deer, not only the bullet... so we would have to count in the the grass behind it, where all the blood will fall and the hill that 'catches' the bullet... also everything between the shooter and the deer + the shooter himself...
Like a sack of rice we must take the planet to conserve all energy in this event... better still the universe...
And while we would have now 'conserved' all the energy for the event, for the deer in the system there is a loss as there is a loss to the bullet...
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Unread 07-26-2012, 09:14 PM
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Re: Needed Energy for killing.... is it a myth??

I think the standard kinetic energy requirements are a good start but not the only designation. I have dispatched two Water Buffalo with a 44 mag pistol with no problems at 75 and 100 yards. This is due to placement and bullet construction. I like the taylor formula better. This is bullet cal size in inches X weight X velocity divided by 7000. You can compare different cartridges by the factor they produce. this puts a large emphasis on bullet weight and diameter. This factor and the rule of 1000 ft lbs for deer , 1500 for elk , and 2000 for moose and larger is fairly safe. However, take in consideration that a good placed shot with a well constructed bullet and good expansion and penetration generally always works. Hope this helps
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Unread 07-27-2012, 12:40 PM
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Re: Needed Energy for killing.... is it a myth??

Holy dead thread revival

Energy is just part of the equation, construction and impact velocity are just as important. And they all take a back seat to placement (but that's another discussion)

I figure it like this
A. = bullet properties (weight, construction)
B. = Impact velocity
C. = Energy

A+B+C = 1 if less than 1 bad juju, if more than 1 you gots your mojo.

If A,B, and C are all up to snuff or more than, then your good
If any one is lacking for that shot then you really should pass
Keep in mind the animals we shoot for food and display are not bullet proof. Contrary to popular belief, they bleed and die just like they did a hundred years ago. Being competent with a given rifle is far more important than impressive ballistics and poor shootability. High velocity misses never put a steak in the freezer.

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