Energy Transfer

[Boomer]

So I witnessed an Elk being shot once. A big Elk mind you. The distance was 560 yards. The cartridge was the 270 Winchester, and the bullet was the 130 TSX. Said bull was struck through the top of the heart. And the bullet went clean through. No CNS and no bone. Yet he went down like he was electrocuted. In fact, his head hit the ground so hard that he broke teeth. Then I saw a bull of very similar size struck with three bullets in the heart lung area at 75 yds as he trotted broad side to the rifle. One shoulder was pulverized. The cartridge was the 280 AI, the bullet the 140 TTSX, and every one was recovered. This bull showed absolutely zero reaction to the bullet until he just simply tipped over.

Energy dump? Energy transfer? Blood loss? Taking a dump? What happened?

I quit worrying about it. But I have noticed diaphragm shooters prefer frangible bullets.

As to the original quote. The dumbest thing I've ever read. Or at least close to it.

We commonly think of a CNS shot as one which strikes the brain or spine, but Nathan Foster suggests that mammals have numerous nerve bundles, and that when one of these nerve bundles is destroyed by a bullet, the result is instantaneous death. One example of a nerve bundle is the Thoracic Autonomic Plexus, others include the Pulmonary Plexus, and branches of the Vegus nerve.

Doktari, Kevin Robertson suggests that the heart at any point in time might be empty, full, or on its way to emptying or on its way to filling. Consider a container full of fluid; if hit with a bullet, it explodes dramatically, but if less than full, the effect is less dramatic, or perhaps not dramatic at all. If the occurrence of the bullet strike is in coincidence with the heart full of blood, the heart explodes, and death is instantaneous. This event does not require a fragile bullet that grenades, or an impact velocity in excess of 3000 fps. If the coincidence of the bullet strike occurs when the heart is empty or only partially filled, the result is not spectacular, and death is not instantaneous, even if the bullet grenades, and even if the bullet impact is in excess of 3000 fps. Its simply a matter of chance, whereas placing a bullet into a nerve bundle produces uniform results. If the bullet fails to destroy a nerve bundle, or fails to dramatically destroy the heart, the result is a longer passage of time before the brain's deprivation of oxygen results in death.

 

[martinbns]

This is pretty technical to me.

I think you match both bullet and velocity to the intended target and hopeful range. I like TSX bullets from 300 Win Magish cartridges for large animals say 350 pounds and up or with thick skins. Pretty much in the ungulate category in NA that means elk or moose. I want a tough bullet driven pretty hard, you get violent expansion and penetration hopefully two holes but not every time.

For smaller slightly built animals I like more frangible bullets in more moderate velocities. My go to Deer rifle was a 308 loaded with a 150 gr BTip as I seldom ever shoot anything outside 300 yards and with this combo you get violent expansion and quick kills.

Whether that energy transfer or hydrostatic shock or just pulverizing the boiler room I don't really know or care that much.

 

[madashell]

Full Metal Jacket head shots ....

 

[stubblejumper]

A good discussion, but getting back to the original question. Given one specific expanding bullet, what effect does velocity have on energy transfer? If we increase the velocity, does the energy transfer increase or decrease? If we reduce the velocity, will the energy transfer increase or decrease? Will reducing the velocity of the same bullet increase or decrease expansion?

 

[c-fbmi]

Boomer, a heart can never be empty or partially filled as you state because the blood system of all mammals is a closed full system, the same as a hydraulic system, which in fact is exactly what it is. Empty heart = dead animal..............I do understand what you are saying, but at no time can a heart be empty, it may be in it's fully contracted state holding very little blood, or it may be in it's fully expanded state being gorged with blood, but at no time can it be partially full or completely empty, or any state in between.

 

[Superbrad]

A good discussion, but getting back to the original question. Given one specific expanding bullet, what effect does velocity have on energy transfer? If we increase the velocity, does the energy transfer increase or decrease? If we reduce the velocity, will the energy transfer increase or decrease? Will reducing the velocity of the same bullet increase or decrease expansion?

If you increase the velocity, you increase the energy available for transfer.... Velocity also aides with quicker expansion, so it would stand to reason that added velocity = added energy transfer......

 

[Grawfr]

A good discussion, but getting back to the original question. Given one specific expanding bullet, what effect does velocity have on energy transfer? If we increase the velocity, does the energy transfer increase or decrease? If we reduce the velocity, will the energy transfer increase or decrease? Will reducing the velocity of the same bullet increase or decrease expansion?

Velocity has no effect whatsoever on energy transfer. A bullet enters the target with a fixed amount of kinetic energy (mass, speed). As long as that bullet ends up at zero speed and still within the target, it will have transferred all of its energy to the target, regardless of the speed or mass it came in with. If the bullet goes through the target and leaves with some residual energy, it's a whole different matter and there's too many variables to calculate.

Velocity and bullet deformation or tumbling would affect energy transfer rate (energy/time), but given that the bullet gets to a full stop within a fraction of a second anyway, it's kinda meaningless.

 

[legi0n]

Nonsense. Higher velocity increases expansion. In my experience, light fast bullets kill quicker than big, heavy, slow ones.

The Brits thought differently during the Boer wars.

 

[stubblejumper]

Velocity has no effect whatsoever on energy transfer. A bullet enters the target with a fixed amount of kinetic energy (mass, speed). As long as that bullet ends up at zero speed and still within the target, it will have transferred all of its energy to the target, regardless of the speed or mass it came in with. If the bullet goes through the target and leaves with some residual energy, it's a whole different matter and there's too many variables to calculate.

Velocity and bullet deformation or tumbling would affect energy transfer rate (energy/time), but given that the bullet gets to a full stop within a fraction of a second anyway, it's kinda meaningless.

You are missing the fact that if the same bullet enters the media with more velocity, it has ,more energy to transfer. So if it stops within the media in both instances, it has transferred more energy to the media. And if it enters the media with more velocity, it can actually exit the media, and still have transferred more energy than the slower bullet that stopped in the media.

 

[legi0n]

Energy transfer is a product of velocity and bullet expansion, not a product of time..... The faster a bullet moves, the more energy it has to transfer, so while it may "stay in the animal for less time" it will transfer more energy per millisecond than a slower moving counterpart....

Really, if comparing the two on an exactly identical pass through shot, with proper billet for velocity, it's a chicken egg argument....

Energy is force by distance. Force is the rate of change of momentum. So it is the slowing of the bullet that transfers energy.
In the Mythbusters episode where they shot the 50BMG into the swimming pool, the higher velocities slowed faster.
So that would be your answer.

Juster is right, energy transfer is a function of velocity change which in this case is a function of target tissue resistance over time.
So in the end, the energy dump is a function of time.
If the bullet remains inside the target, then clearly all it's energy has been transferred.
If it passes through, only a fraction is transferred to the target.
If you want to compute how much, fit your deer with chronographs before and after the impact point, a bullet trap behind the exit chrony and pm me the velocities and the retained projectile weight.
I'll be happy to do the math for you.

 

[legi0n]

You are missing the fact that if the same bullet enters the media with more velocity, it has ,more energy to transfer. So if it stops within the media in both instances, it has transferred more energy to the media. And if it enters the media with more velocity, it can actually exit the media, and still have transferred more energy than the slower bullet that stopped in the media.

that sounds fair but it is difficult to quantify unless we know both the impact and the exit velocities.

so, this whole thread is just an intellectual exercise unless you can prove that the same bullet sheds more velocity when the impact speed is higher (through the same target of course).

 

[FLHTCUI]

I am not interested as to whether energy transfer kills the animal or not, just in whether more velocity increases or decreases energy transfer. But please comment on expansion vs velocity, as I also hear people stating that a bullet is moving too fast to expand, and that reducing the velocity would increase expansion.

I like the purple kook- aide cause it tastes good.

So having said that there is nothing that's shoots flatter hits harder that a Weatherby.

Aside from that I've got nothing ...well maybe watch some ballistic gelatin vids to see the hydrostatic shock destroy the simulated animal body tissue.

It is an interesting topic that has been debated since Roy Weatherby created his tag line on performance.

Tight Groups,
Rob

 

[stubblejumper]

Juster is right, energy transfer is a function of velocity change which in this case is a function of target tissue resistance over time.
So in the end, the energy dump is a function of time.

Actually that theory is badly flawed. As an example look at the case where a bullet travels lengthwise through a moose and stops in the moose after traveling through four feet of moose. Then look at another situation where the same bullet was fired broadside into the shoulder and only penetrated one foot of moose. In both cases the moose absorbed the exact same amount of energy, and the same amount of velocity change, but in the case of the moose shot lengthwise, the bullet penetrated four times as much tissue and it would have taken longer for the bullet to come to a stop, In this case the time that the bullet penetrated has absolutely no bearing on the amount of energy that the bullet transferred into the moose.

that sounds fair but it is difficult to quantify unless we know both the impact and the exit velocities.

so, this whole thread is just an intellectual exercise unless you can prove that the same bullet sheds more velocity when the impact speed is higher (through the same target of course).

Are you a big game hunter? If you are,have you noticed that when you shoot game animals at close range, that there is usually more internal damage than when you shoot animals at long distance with the same load?

 

[H4831]

Guys, I would like to point out that the theory of hydro static shock as killing power has been around for a very long time.
It was still the 1930's when some gun editor wrote in his magazine that the 220 Swift was so fast that hydro static shock would kill any animal hit by the speedy bullet! Hunters argued about that for years.

 

[legi0n]

Actually that theory is badly flawed. As an example look at the case where a bullet travels lengthwise through a moose and stops in the moose after traveling through four feet of moose. Then look at another situation where the same bullet was fired broadside into the shoulder and only penetrated one foot of moose. In both cases the moose absorbed the exact same amount of energy, and the same amount of velocity change, but in the case of the moose shot lengthwise, the bullet penetrated four times as much tissue and it would have taken longer for the bullet to come to a stop, In this case the time that the bullet penetrated has absolutely no bearing on the amount of energy that the bullet transferred into the moose.



Are you a big game hunter? If you are,have you noticed that when you shoot game animals at close range, that there is usually more internal damage than when you shoot animals at long distance with the same load?

Actually your example proves the theory.
While the bullet travels 4 ft of muscle the resistance is lower but the time to stop is longer.
When the bullet hits bone, the resistance is higher and the time the bullet stops is shorter.
Given that the energy transfer is the same, we can compute the resistance of moose muscle over moose muscle and bone.

Also, this thread is not about the knockout power but about the energy transfer which may or may not be related to the KO power.

 

[FLHTCUI]

http://www.ballisticstudies.com/Knowledgebase/Game+Killing+Fundamentals.html

Some good reading there if one wants to drink a pot of coffee or tea...
And H4831, guys are still discussing those same points today
Rob

 

[curseyou]

Two bullets, same caliber and weight, same velocity... same bullet placement... one goes right through, one stops on the far side and does not exit... that bullet transferred all of it's energy.

yes, but this doesnt make for a kill. the point isnt to push them over. it is to crush vital organs and exsanguinate your dinner. passing through or stpping on the far side of the hide makes no difference.

-how big is the hole the bullet path made? (caliber and expansion)
- what vitals did the bullet pass through? (aim, luck, and the beasts orientation)
- any secondary traumatic effects like hydrostic shock. (a major blood vessel may have been missed by the bullet path, but could still ruptured by the tissue deformation a very high velocity bullet can impart. this is much overhyped imho, as the first two items are overpoweringly important, and this one nearly falls of the map.

 

[Grawfr]

A good discussion, but getting back to the original question. Given one specific expanding bullet, what effect does velocity have on energy transfer? If we increase the velocity, does the energy transfer increase or decrease? If we reduce the velocity, will the energy transfer increase or decrease? Will reducing the velocity of the same bullet increase or decrease expansion?

You are missing the fact that if the same bullet enters the media with more velocity, it has more energy to transfer. So if it stops within the media in both instances, it has transferred more energy to the media. And if it enters the media with more velocity, it can actually exit the media, and still have transferred more energy than the slower bullet that stopped in the media.

Stubble, you both asked and answered your own question. So what is it you really want to know? What kills better?

It's a function of too many variables, the first one being shot placement. For two identical placed shots of the same mass and velocity? It's a function of which bullet tumbles or expands the best. What if one bullet leaves the body but not the other? You already answered that. If you try to compare different bullets, mass, speed, placement, etc. you cannot have a meaningful comparison.

 

[nowarningshot]

What you are really talking about when talking about terminal performance, is range and velocity. At short range many non premium cup n core bullets do a excellent job. When range increases and velocity decrease bullet design allows the premium bullets to still penetrate and expand. There comes a point when the tougher premium bullets are prone to pinhole wounding unless bone is hit. At that point the more frangible bullets, ones that expand sub 2000ft/sec come into their own. Bullets like the Bergers and Amax expand sending large fragments to cause wounding often to as little as 1600ft/sec. The danger of those projectiles is wide shallow....bullet blow up....at short range when travelling at high speed or encountering major bone such as a femur or shoulder socket.

Many manufacturers struggle to find the right balance of short and long range terminal performance. Remember that the vast majority of shots are short range. Many of the value cup n core bullets killed game for our grandfathers, and today that same game is not wearing kevlar. I still prefer premium projectile, since i reload, and the cost is insignificant as compared to fuel, equipment, time off.....etc.

 

[madashell]

What you are really talking about when talking about terminal performance, is range and velocity. At short range many non premium cup n core bullets do a excellent job. When range increases and velocity decrease bullet design allows the premium bullets to still penetrate and expand. There comes a point when the tougher premium bullets are prone to pinhole wounding unless bone is hit. At that point the more frangible bullets, ones that expand sub 2000ft/sec come into their own. Bullets like the Bergers and Amax expand sending large fragments to cause wounding often to as little as 1600ft/sec. The danger of those projectiles is wide shallow....bullet blow up....at short range when travelling at high speed or encountering major bone such as a femur or shoulder socket.

Many manufacturers struggle to find the right balance of short and long range terminal performance. Remember that the vast majority of shots are short range. Many of the value cup n core bullets killed game for our grandfathers, and today that same game is not wearing kevlar. I still prefer premium projectile, since i reload, and the cost is insignificant as compared to fuel, equipment, time off.....etc.

THIS is what I think we should expand on vs all the back an forth.

C&C tends to work well generally to this range/velocity, yet mono bullets in same range/velocity tend to do this. Etc. etc.

I think with this approach one could make a ROUGH table and actually be able to USE the information.