This is way over my head, gents, but I find the opinions on physics fascinating. One question of an above post, an arrow's energy does not kill the animal does it? Is it not the slicing of flesh and blood veins that causes the animal's demise?
You guys are really deep thinkers compared to a simpleton such as myself.
Cheers and keep 'em coming.
Cal

Cal I am like you and agree about the arrow.

For an arrow to be most effective its broad head needs to be razor sharp and pyt through the heart or major blood vessel.

My take on energy transferance-not answering the OP question- is that the faster an bullet is traveling (given both are the same shape dimensions weight etc) the more damage it will do if the construction will allow it to hold together. Some of this damage, to my mind, is caused by the shock or pressure wave the bullet creates in the animal.

Most bullets designed for slower velocities work well because they expand enough yet still give deep penetration.

Back to the OP. I think it is horses for courses. Hit any animal in the CNS with anything and they are down. Say in a side on shot, which ever causes the most internal damage, means less tracking but two holes normaly means easier tracking if animal does not drop on the spot or close to. Just my thoughts.

quote:

Originally posted by cal pappas:
This is way over my head, gents, but I find the opinions on physics fascinating. One question of an above post, an arrow's energy does not kill the animal does it? Is it not the slicing of flesh and blood veins that causes the animal's demise?
You guys are really deep thinkers compared to a simpleton such as myself.
Cheers and keep 'em coming.
Cal

Cal,

An arrow's energy kills the animal since the arrow's mechanical energy is the necessary velocity for penetration and for the broadhead to cut tissue. (A razor blade without motion does not cut, motion is mechanical energy.) The energy transferred essentially creates the wound.

Nothing is much different with a bullet. The bullet's mechanical energy, in the form of velocity, is necessary for penetration, and in the case of a soft point for the expansion of the bullet, as well as the displacement of tissue. Again, the energy transferred essentially creates the wound.

[Which is why Gerard is correct when he asserts that the faster of two similar bullets will create more wound volume in those cases where neither exits. A point of contention is found in those cases where one or both bullets exit, and then the question could be answered if one were to know how much energy the bullet retained at exit (it is known that energy is essentially zero at the conclusion of a bullet that does not exit,) since the amount of energy expended within the animal would determine wound channel volume - of similar bullets, similar target course, ect. Impact energy - exit energy (or for a bullet that did not exit, terminal energy of zero) = expended energy. The greater energy expended within the animal, the greater the wound volume.]

JPK

quote:

Originally posted by JPK:

quote:

Originally posted by cal pappas:
This is way over my head, gents, but I find the opinions on physics fascinating. One question of an above post, an arrow's energy does not kill the animal does it? Is it not the slicing of flesh and blood veins that causes the animal's demise?
You guys are really deep thinkers compared to a simpleton such as myself.
Cheers and keep 'em coming.
Cal

Cal,

An arrow's energy kills the animal since the arrow's mechanical energy is the necessary velocity for penetration and for the broadhead to cut tissue. (A razor blade without motion does not cut, motion is mechanical energy.) The energy transferred essentially creates the wound.

Nothing is much different with a bullet. The bullet's mechanical energy, in the form of velocity, is necessary for penetration, and in the case of a soft point for the expansion of the bullet, as well as the displacement of tissue. Again, the energy transferred essentially creates the wound.

[Which is why Gerard is correct when he asserts that the faster of two similar bullets will create more wound volume in those cases where neither exits. A point of contention is found in those cases where one or both bullets exit, and then the question could be answered if one were to know how much energy the bullet retained at exit (it is known that energy is essentially zero at the conclusion of a bullet that does not exit,) since the amount of energy expended within the animal would determine wound channel volume - of similar bullets, similar target course, ect. Impact energy - exit energy (or for a bullet that did not exit, terminal energy of zero) = expended energy. The greater energy expended within the animal, the greater the wound volume.]

JPK

Since it is almost impossible to measure the velocity of a bullet after it exits the animal, the computation of energy not captured by the animals body is also near impossible to determine. Also it is probably impossible to measure the wound volume in an animal and we are left with a subjective determination of that volume. In a subjective evaluation of wound volume, personal bias can lead to significant error. You know, "You see what you want to see!". Consequently, we need to take any field observation of wound volume with a large grain of salt.

465H&H

quote:

Originally posted by cal pappas:
This is way over my head, gents, but I find the opinions on physics fascinating. One question of an above post, an arrow's energy does not kill the animal does it? Is it not the slicing of flesh and blood veins that causes the animal's demise?
You guys are really deep thinkers compared to a simpleton such as myself.
Cheers and keep 'em coming.
Cal

Cal,

We will expect you to give us credit in your next book!


465H&H

A bullets energy is "kinetic energy" not mechanical energy. As such very little kinetic energy transfers in an inelastic collision.

[URL=http://s33.photobucket.com/user/jwp475/media/BallisticsPendulum.gif.html] [/URL

Most will not understand the diagram but surface it to say that kinetic energy is not measurable only momentum is measurable. Kinetic energy is CALCULATED.

Ah yes the bullet possesses kinetic energy ( a form of energy) this is true however energy is readily converted in form so that this kinetic energy converts to mechanical energy, heat energy and acoustic energy amongst other.

The act of pushing target material away from it path in the target is a energy dependent event

Bullets are PASSIVE KINETIC ENERGY PENETRATORS

All that the are and do in terms of our ballistics model is energy related.

In fact the physical definition of our ballistics system is a energy related event from ignition of the primer to the strike and penetration of the projectile. The fact that we are dealing with the physical property of MASS makes it so.

quote:

Originally posted by jwp475:
A bullets energy is "kinetic energy" not mechanical energy. As such very little kinetic energy transfers in an inelastic collision.

[URL=http://s33.photobucket.com/user/jwp475/media/BallisticsPendulum.gif.html] [/URL

Most will not understand the diagram but surface it to say that kinetic energy is not measurable only momentum is measurable. Kinetic energy is CALCULATED.

Momentum is a vector force, it has a direction. That's what makes the wooden block move in the above diagram, what makes your shoulder recoil with the rifle, and what makes the bad guy jump twenty feet backwards when shot with a 9mm in the movies.

Kinetic energy is what makes the milk jug explode on bullet impact, what carves the temporary cavity, and what causes tissue damage far away around the bullet path.

quote:

Originally posted by Philip A.:

quote:

Originally posted by jwp475:
A bullets energy is "kinetic energy" not mechanical energy. As such very little kinetic energy transfers in an inelastic collision.

[URL=http://s33.photobucket.com/user/jwp475/media/BallisticsPendulum.gif.html] [/URL

Most will not understand the diagram but surface it to say that kinetic energy is not measurable only momentum is measurable. Kinetic energy is CALCULATED.

Momentum is a vector force, it has a direction. That's what makes the wooden block move in the above diagram, what makes your shoulder recoil with the rifle, and what makes the bad guy jump twenty feet backwards when shot with a 9mm in the movies.

Kinetic energy is what makes the milk jug explode on bullet impact, what carves the temporary cavity, and what causes tissue damage far away around the bullet path.

It is rear ward momentum that pushes you back, frontal area, direct applied force, hydraulic pressure, and momentum transfer is what creates the wound channel. Most of a bullets energy is transformed into others forms of energy mostly thermal.

You are correct the pendulum measures momentum.

jwp475,

The problem with your often repeated illustration is that there are no inelastic collisions in shooting or hunting.

Momentum, like kinetic energy, is possessed by an object with mass and motion, but it is mechanical energy which causes trauma. We know this because momentum is conserved but kinetic energy can dissipate, here mainly through work, ie. through conversion to mechanical energy. Momentum cannot.

JPK

Sorry JPK, a bullet strike is most certainly an inelastic Collision. There are only 2 types of collision "elastic" and "inelastic". An inelastic collision is one where one or both of the colliding bodies change shape.

quote:

Originally posted by jwp475:
Sorry JPK, a bullet strike is most certainly an inelastic Collision. There are only 2 types of collision "elastic" and "inelastic". An inelastic collision is one where one or both of the colliding bodies change shape.

Yes, my point exactly.

Both change shape. Target and bullet.

The effectiveness of the Keith bullet ( semi wadcutter ) often get brought up in discussion as opposed to a RN or ogival bullet of same weight ?

The question is why is the Keith bullet so effective ?

From a physical point of view if both are fired at same velocity and both are of same weight why does the Keith bullet outperform the RN bullet?

Both bullets have the same momentum ( = amount of motion) both have the same amount of kinetic energy
( = available potential to do work)

The answer lies is sectional density or from a physical perspective energy density.

The effective SD of a wadcutter is bigger than a RN or ogival bullet of same weight because the physical definition of SD has to include the effective projected surface area of the projectile.

It means that the wadcutter has a larger concentration of projected energy than the RN and thus has more potential to do work on the target.

from a classic mechanics perspective it is not momentum that does damage but the change in momentum.

Change in momentum derived is equal to Force and force applied for a period of time is work. The only way the bullet can do damage is when momentum to transferred to the target, without that gift of motion there is no damage. The wadcutter induces less drag per unit distance of penetration thus loses motion per unit distance thus will do damage over a longer distance than the RN which expends all of its motion in a short distance.

it is the same principle when comparing a blunt vs sharp knife. Knives "cut" by means of application of force ( work) on a surface that breaks the bonds of the target material hence causing the laceration. in the sharp knife the energy is concentrated more than the blunt knife the energy density is higher for the sharp vs blunt knife

It means that the semi wad utter has a larger MEPLAT than the round nose. This enables the semi wadcutter the crush more tissue and spread its amount of direct applied force over a greater area.

jwp475
" It means that the semi wad utter has a larger MEPLAT than the round nose. This enables the semi wadcutter the crush more tissue and spread its amount of direct applied force over a greater area."

This is unfortunately not correct:
The Keith bullet , which incidentally is actually the design endpoint of 3 prior designs actually the opposite to what you profess.

The Keith bullet increases the sectional density , hence then BC and energy density of the bullet by having a 65 or 70 % meplat on the end of a shortened truncated cone . This drastically reduces the effective presenting surface when compared to the RN bullet.

It effectively concentrates its energy over a smaller area then the RN and that is why they are so effective.

quote:

Originally posted by ALF:
jwp475
" It means that the semi wad utter has a larger MEPLAT than the round nose. This enables the semi wadcutter the crush more tissue and spread its amount of direct applied force over a greater area."

This is unfortunately not correct:
The Keith bullet , which incidentally is actually the design endpoint of 3 prior designs actually the opposite to what you profess.

The Keith bullet increases the sectional density , hence then BC and energy density of the bullet by having a 65 or 70 % meplat on the end of a shortened truncated cone . This drastically reduces the effective presenting surface when compared to the RN bullet.

It effectively concentrates its energy over a smaller area then the RN and that is why they are so effective.

Sorry but that is not correct. Some of the so called "Keith" semi wad cutters have rather large meplats. Same caliber same weight have identical sectional densities.

Energy does not kill. Correct placement of the bullet and the right bullet construction for the task at hand does.

JWP 475:

read what I write !

Yes the Meplat is large, 70% of caliber for the later model Keith bullet but it is considerably smaller than the wetted surface of a round nose bullet of same caliber.

go calculate it ! The formula for the surface of a disc is pi.r squared and for the effective presenting surface of a hemispherical RN 2 x pi.r squared

It is impossible for a Wadcutter and a RN of similar caliber of same weight to have the same Sectional density !

As to energy no killing ? really Gerard ! The only way your bullet can kill is when work is done on the target ! the SI unit for work is defined as the Joule i.e. the Newton.meter i.e. a force of 1 Newton applied over a distance of 1 meter

The SI unit of energy is the Joule so in effect when the bullet Does work on the target it is by virtue of gifting energy to the target.

Alf,

quote:

Alf: As to energy no killing ? really Gerard ! The only way your bullet can kill is when work is done on the target !

quote:

Alf: read what I write !

Follow the advice you give.

I said: "Energy does not kill. Correct placement of the bullet and the right bullet construction for the task at hand does."

If the energy did the killing, every time a person fired the first shot, it will also be his last because the energy the rifle develops will kill the shooter. The energy that the rifle develops is equal to that which the bullet has when it unplugs from the barrel. The rifle presents that energy in a different manner to the shooter, so that the rifle does not kill him.

It seems to me that energy does the damage. Bullet construction determines how that energy is used to destroy tissue.

465H&H

The reason the rifle does not kill you has to do with the force impulse , the sectional density of the rifle's presenting part to the shooter and the energy density of the recoiling surface that is in contact with the shooter.

A 7 pound ( = 49,000 grain ) rifle firing a 140 gr bullet shows the difference is sectional density between the bullet and the gun and its recoiling parts

If the butt of the rifle were a sharp spike it would most certainly have the potential to kill the shooter !

We cannot get away from it, bullets in motion are kinetic energy penetrators, they do their work by transferring energy to their targets, what the target does with that energy is totally dependent on the mechanical properties of the target.

You can try and come with some illogical or simply silly arguments about bullet placement ? we all know bullet placement is vitally important. As to construction, that is simply the willful manipulation of how energy will be transferred to the target when the projectile meets resistance to penetration. But facts are facts.


Out ballistics system from a physical perspective involves the thermodynamic conversion of a solid granular energetic propellant from a solid to a gas , the energy contained within the propellant is converted to kinetic energy as the molecules within the gas move at very high speed colliding with each other and the container which encloses the gas mass.

The gas does work ( exerts force over time) on the bullet of certain sectional density causing it to accelerate down the bore. The bullet now has gained the converted energy from the propellant in the form of kinetic energy.

Our system is rather inefficient because only a 1/3 of the total potential energy contained in the powder charge ends up as bullet kinetic energy, the rest is lost to the system or used in the recoil of the gun.

When the bullet impacts the target it transfers its energy to the target by transferring motion ( momentum ) to the tissue matter which accelerates away from the penetrating bullet.


This energy is termed mechanical energy because of its ability to transport matter ( move matter over distance as observed by high speed radiography )

Some of the bullet's energy is converted to heat energy, this heat energy does little damage because it has a very short contact time with the tissue, some energy is converted to sound, the sonic wave that is propagated in the target moves at greater speed than the bullet in the target, it does not transport matter so it does not participate in what we see as a wound.

This energy does however have the potential ability to alter nerve conduction by virtue of it's effect on transmembrane ion transport. This is basically the same principle used to treat certain painful orthopaedic conditions using ultrasound ( orthotripsy)

quote:

Originally posted by 465H&H:
It seems to me that energy does the damage. Bullet construction determines how that energy is used to destroy tissue.

465H&H

And shot placement determines what tissue is destroyed by the applied energy via the bullet given it's construction.

I.e., energy kills.

JPK

Energy and bullet construction. Horsepower and traction. The first will give you an idea of how much how much work you could do, if you can get it hooked up.

Bullet construction and traction can optimize the energy available, in the material needed but it can't make power that isn't there.

One of the oldest physics experiments out there

Dropping a cannon ball of known weight ( mass) from a known height into a bowl of sand and then measureing crater diameter. The kinetic energy of the ball is linear to the diameter of the crater ! Off course the more precise calculations would include contants related to the type of sand in the bowl.

The size of the temporary cavity in a visco elastic medium is directly proportional to the energy deposited to the medium per unit distance of penetration, also a very old and established experiment.

Anything that moves carries energy with it. Any amount of energy can kill, if it is applied correctly. More or less energy cannot kill more or less efficiently, the shape of the object and how the energy is applied is what counts.

Many large animals have been killed for slaughtering with a 22 long to the brain. It has 32ft-lb of energy at the muzzle.

Animals are killed with arrows that weigh 400gr and that are going at 300fps. The energy is more than double that of the .22 at 80ft-lb.

A 300RUM loaded with a 180gr hollow point match bullet going at 3250fps has 4223ft-lb of energy. Shoot an animal on the shoulder at short range and it runs away on three legs. Neither the animal nor the shooter dies because the application of energy to each is incapable of doing this. The rifle has a recoil pad and weighs enough so that the recoil impulse does not kill the shooter. The bullet uses the available energy it has on turning to dust, breaking the legbone and making a large diameter, shallow wound channel.

The amount of energy that any moving object carries with it means nothing if it is not applied correctly. Energy does not kill and more is not always better.

As Dogleg says, you have to hook it up.

quote:

Originally posted by Gerard:

The amount of energy that any moving object carries with it means nothing if it is not applied correctly. Energy does not kill and more is not always better.

As Dogleg says, you have to hook it up.

Exactly, Gerard. Broken record here. Paper ballistics don't tell much. As a handgun hunter, I have seen and killed animals that shouldn't succumb to rounds "generating" (remember energy is calculated and not measured) such meager energy numbers, but they kill with aplomb. Killed a 1,500-lb water buffalo recently with a load that calculates out to 1,276 ft-lbs of ME and the bovine apparently wasn't aware it wasn't enough.

Gerard:

Exactly , did anyone actually infer otherwise ?

Calculated Kinetic energy is a " potential" only. The same applies to the potential energy contained in the caloric value of a mass of energetic propellant.

A 8000 ft pound elephant killer is perfectly useless if the elephant is shot in the foot. This is not in dispute.

What is in dispute is the notion that somehow it is not energy transfer that actually causes damage in penetrating wounds.

Whether it is a knife cutting through tissue, a bullet or a spear penetrating flesh, the only way this penetration can occur is if energy is transferred to the target matter allowing passage by the penetrator. It is as simple or a complex as that.

quote:

Originally posted by cal pappas:

quote:

Personally, I like two holes.

JPK:
I guess the photo illustrates the two hole theory. This is from a caribou I shot last week. Two is certainly better than one.
Cal

What Bore rifle did you use?
Bill

Cal.

Blood has to in the blood vessel and must be in motion under pressure to do it's work. Not only that the blood has to be oxygenated.

What I'm trying to get at is that visible blood outside the body is not a perquisite as an indicator of a animals impending demise.

One can bleed just as badly internally with no visible blood and be in as much trouble as your caribou.

Two holes vs one hole is not an indicator how quickly your animal is going to die.

It is the very first lesson you have to learn when dealing with trauma.


Animals ( humans) bleed to death without a single drop of blood leaving their body !

What counts is a big hole through the heart to hasten the bleeding to death. What happens before and after the vital organs are hit is of little importance. Best is to puncture both lungs and the heart or to cut off the arteries above the heart.

Santa Claus

quote:

Originally posted by Bill Cooley:

quote:

Originally posted by cal pappas:

quote:

Personally, I like two holes.

JPK:
I guess the photo illustrates the two hole theory. This is from a caribou I shot last week. Two is certainly better than one.
Cal

What Bore rifle did you use?
Bill

.450-400 3" Harrison and Hussey boxlock ejector. No bore rifle.

Gents: I'm continuing to be fascinated by your information here.
Cal

quote:

Originally posted by ALF:
Cal.

Blood has to in the blood vessel and must be in motion under pressure to do it's work. Not only that the blood has to be oxygenated.

What I'm trying to get at is that visible blood outside the body is not a perquisite as an indicator of a animals impending demise.

One can bleed just as badly internally with no visible blood and be in as much trouble as your caribou.

Two holes vs one hole is not an indicator how quickly your animal is going to die.

It is the very first lesson you have to learn when dealing with trauma.


Animals ( humans) bleed to death without a single drop of blood leaving their body !

Yea, but if the death isn't instant the game is a hell of a lot easier to find with a blood trail like the one Cal's caribou left!

JPK

...if there ain´t no velocity...nothing will happen

4 parameters has to be fullfilled in order to make a kill:
Eventually there has to be a velocity 1)...there has to be a mass/weight 2) and the mass must be of a certain size 3). If all these things are present then you just have to hit right.4).
If things doesn´t Work from here add pixidust..