running deer

[Crankbender]

When an animal instantly collapses from a torso hit, the usual cause is blunt trauma to the spinal column caused by temporary cavitation. Scroll down to the last article here for a more detailed explanation:

http://firearmstactical.com/briefs28.htm

This is exactly true. If you use a bullet at a velocity that produces lots of explosive force and hit NEAR the spine you get instant paralisis. The more explosive force the farther away you can get from the spine and still get paralysis.


My personal experience also shows that you are much more likely to see this effect on young small deer.


Hit a deer with a regular 130g bullet from a 270 at 100 yards just above center of the lungs and there is a very good chance it will drop on the spot.

 

[tjhaile]

Centrefire rifles typically create a large enough temporary cavity to stretch tissue beyond its breaking point. This is why rifle bullets often create wound cavities much larger than the diameter of the expanded bullet.

 

[bigbull]

I have shot a bunch of deer and have had 3 run any distance after they were hit, one female was hit through the lungs ( I thought) but I never found her after I tracked her for the better part of three hours, can't explain what happened! The second one was shot through the lungs and went about 50 yards and the third was shot head on through the chest and ran about 60 yards, most all the others were shot with various 35 calibers, 35 Rem, 358 Win and 350 Rem Mag, all with a 200gr bullet, I must say that the deer shot with the 35's went much less distance after they were hit than with the othe calibers I have used (444 Marlin, 308 Win and 280 Rem), I can't explain it, needless to say I like hunting with the 35 calibers.
bigbull

 

[Jordan Smith]

What you are trying to say in post #12 is correct, but your physics are a little skewed.

What your shoulder feels is a combination between force and velocity. The force that you feel and the force that the bullet imparts on the animal is EXACTLY the same. It is just applied to your shoulder more gradually than it is on the animal. The momentum is what actually does most of the damage (to your shoulder and to the animal). The rifle has about 20 times more momentum than does the bullet, which is why it takes so much more resistance from your shoulder to stop the rifle. The bullet certainly doesn't have enough force to knock an animal down, and your figure of 4000lbs (which is WAY high) would not only knock the animal down, but break every bone in its body.

You are right about the fact that the difference is in the speed of transfer of the energy/force/momentum. It is not an apples to apples comparison, and it quite physically complex to understand the relationship between what the shooter feels, and what the animal feels, due to the fact that the energy and momentum of the bullet are being used to transform the shape of the bullet (and likewise the flesh of the animal), which is what causes the temporary cavitation, NOT a simple massive amount of force.

Post #20 is pretty bang on.

Just thought I'd throw in my $0.02

 

[sjemac]

What you are trying to say in post #12 is correct, but your physics are a little skewed.

What your shoulder feels is a combination between force and velocity. The force that you feel and the force that the bullet imparts on the animal is EXACTLY the same. It is just applied to your shoulder more gradually than it is on the animal. The momentum is what actually does most of the damage (to your shoulder and to the animal). The rifle has about 20 times more momentum than does the bullet, which is why it takes so much more resistance from your shoulder to stop the rifle. The bullet certainly doesn't have enough force to knock an animal down, and your figure of 4000lbs (which is WAY high) would not only knock the animal down, but break every bone in its body.

You are right about the fact that the difference is in the speed of transfer of the energy/force/momentum. It is not an apples to apples comparison, and it quite physically complex to understand the relationship between what the shooter feels, and what the animal feels, due to the fact that the energy and momentum of the bullet are being used to transform the shape of the bullet (and likewise the flesh of the animal), which is what causes the temporary cavitation, NOT a simple massive amount of force.

Post #20 is pretty bang on.

Just thought I'd throw in my $0.02

The numbers I used were just picked but all come from each other mathematically. So while 4000 ft lbs may not be realistic it is theoretically what the energy would be using those numbers.

One correction: the momentum of the rifle is not and cannot be 20 times that of the bullet. The Law of Conservation of Momentum dictates that the momentum of the bullet and the rifle must be equal and opposite.

The momentum for the rifle and the bullet will be the exact same also. It will be the velocity of each that will be different. A 3kg rifle with a momentum of 12 Newton meters will be moving rearwards at 4m/s. The 10gram bullet it fires will be moving forward at 1200 m/s.

Now you are correct in that the forces are the same in total, but what I am trying to make people understand is that the damage produced by a bullet is primarily due the time it takes for those forces to be dissipated.

Call it what you want, the "effective force" is the force that causes damage. It is a function of the change of momentum divided by the time it takes that momentum to change. So for the rifle, the time it takes the rifle to stop moving backwards is likely somehere in the range of 0.5 seconds to 1 second. Even if we take the lower time the force felt by the shooter will still only be about 24 Newtons. The deer will soak up that momentum in about 0.01 seconds giving an effective force of 1200 Newtons.

All of Newtons laws apply but too many people ignore the time factor that actually allows forces to cause the damage.

 

[Jordan Smith]

The numbers I used were just picked but all come from each other mathematically. So while 4000 ft lbs may not be realistic it is theoretically what the energy would be using those numbers.

One correction: the momentum of the rifle is not and cannot be 20 times that of the bullet. The Law of Conservation of Momentum dictates that the momentum of the bullet and the rifle must be equal and opposite.

The momentum for the rifle and the bullet will be the exact same also. It will be the velocity of each that will be different. A 3kg rifle with a momentum of 12 Newton meters will be moving rearwards at 4m/s. The 10gram bullet it fires will be moving forward at 1200 m/s.

Now you are correct in that the forces are the same in total, but what I am trying to make people understand is that the damage produced by a bullet is primarily due the time it takes for those forces to be dissipated.

Call it what you want, the "effective force" is the force that causes damage. It is a function of the change of momentum divided by the time it takes that momentum to change. So for the rifle, the time it takes the rifle to stop moving backwards is likely somehere in the range of 0.5 seconds to 1 second. Even if we take the lower time the force felt by the shooter will still only be about 24 Newtons. The deer will soak up that momentum in about 0.01 seconds giving an effective force of 1200 Newtons.

All of Newtons laws apply but too many people ignore the time factor that actually allows forces to cause the damage.

I definitely agree with you that the time over which the energy is transferred and the force is applied is what causes the bullet to deform, and ultimately, destroy flesh. However, we still disagree on the momentum issue because the Law of Conservation of Momentum dictates that the momentum of the bullet and the rifle must be equal and opposite in an isolated system. Unfortunately, the system is not isolated. We are not measuring the bullet's momentum at the muzzle, but rather when it impacts the animal.

Between the time the rifle begins to recoil rearward and the time the bullet makes impact, there are several external forces that play on the bullet. There is friction from the rifling of the barrel on the bullet, friction against the forward motion of the bullet from air drag, and there are super-heated gases that jet from the muzzle, propelling the rifle backwards even after the bullet has left the barrel (which is why a muzzle break is so effective in reducing recoil, without detracting at all from the momentum, energy, or force of the bullet). All of these factors contribute to the shooter absorbing far more momentum from the rifle, than the animal absorbs from the bullet.

Other than that, I completely agree with what you're saying

 

[sjemac]

I definitely agree with you that the time over which the energy is transferred and the force is applied is what causes the bullet to deform, and ultimately, destroy flesh. However, we still disagree on the momentum issue because the Law of Conservation of Momentum dictates that the momentum of the bullet and the rifle must be equal and opposite in an isolated system. Unfortunately, the system is not isolated. We are not measuring the bullet's momentum at the muzzle, but rather when it impacts the animal.

Between the time the rifle begins to recoil rearward and the time the bullet makes impact, there are several external forces that play on the bullet. There is friction from the rifling of the barrel on the bullet, friction against the forward motion of the bullet from air drag, and there are super-heated gases that jet from the muzzle, propelling the rifle backwards even after the bullet has left the barrel (which is why a muzzle break is so effective in reducing recoil, without detracting at all from the momentum, energy, or force of the bullet). All of these factors contribute to the shooter absorbing far more momentum from the rifle, than the animal absorbs from the bullet.

Other than that, I completely agree with what you're saying

Of course we could discuss all those factors as well as the surface area over which both impacts are felt and how bullet design contributes to the radial dispersion of energy and the wound thus created and do a 1500 page dissertation but I get paid $500 a day to do that and CGN ain't paying the going rate. I was keeping it simple and at the purely theoretical "perfect frictionless physics world". There are a nearly endless number of variables to account for. The long and short of it is that most hunting rifle bullets disperse enough energy to create a felt impact on the CNS (if they strike relatively close to it) even if the CNS is not actually struck by the bullet. This is what most people mean by "shocking power.

 

[the spank]

My deer huntinmg experiences are extremely limited only having hunted them maybe 3 times and having shot my first this past fall after 3 hours in the stand on my first day out. I took a 6 point whitetail at 338 yards with my model 71 .348 with a 200 grain silvertip winchester factory round. My shot was placed perfectly centre height wise on the body but about 6" back of the front leg, about 4 more than where I was aiming for. The bullet passed completely through the animal, turning half the liver to to a shredded mass more liquid than pieces and leaving the other half intact, and exited without hitting any bones including the rib bones, the exit hole was barely larger than my thunmbnail. After the report of the rifle I heard the bullet impact echo back at me and the deer jumped straight up buckling in the centre like you see in the shows kicking his heels together and then running off. He ran about 25 yards before going down onto his face and falling over on his side. He sat upright for a few seconds and then as I watched through the scope I saw him lay his head down slowly. The amount of damage to the liver and the amount of blood in the cavity when I opened him to gut him astounded me, it took about 25 mins for him to expire before I could go get him. My big surprise I guess was that after all the stories I had heard of my grandfathers exploits with his 348, I was expecting to see the deer literally drop dead in his tracks at the pull of the trigger.Guess it doesnt work that way, should have known that really, I just thought all these guys on tv were making mis-placed shots or using bullets with lousy expansion qualities to be honest. Lesson learned for me. I have come to the conclusion there really is much "shock" factor other than being startled after the "boom" sound of the gun going off. I believe there is just a large amount of energy capable of shredding vitals as the bullet tears through them in my opinion.

 

[Jordan Smith]

Of course we could discuss all those factors as well as the surface area over which both impacts are felt and how bullet design contributes to the radial dispersion of energy and the wound thus created and do a 1500 page dissertation but I get paid $500 a day to do that and CGN ain't paying the going rate. I was keeping it simple and at the purely theoretical "perfect frictionless physics world". There are a nearly endless number of variables to account for. The long and short of it is that most hunting rifle bullets disperse enough energy to create a felt impact on the CNS (if they strike relatively close to it) even if the CNS is not actually struck by the bullet. This is what most people mean by "shocking power.

Amen, and amen.

 

[Jordan Smith]

the spank,

I think what you saw is the large variation in different individual animal's toughness and will to live. Just like humans, some deer can take a hit to the jaw and keep on fighting, while others have a glass jaw and one little flick in the right spot will result in a TKO.

Aside from this factor, the physiological state of the animal at the time of bullet impact has also shown to affect the animal's reaction to the hit. The state of the respiratory and circulatory systems are the two big ones.

 

[the spank]

the spank,

I think what you saw is the large variation in different individual animal's toughness and will to live. Just like humans, some deer can take a hit to the jaw and keep on fighting, while others have a glass jaw and one little flick in the right spot will result in a TKO.

Aside from this factor, the physiological state of the animal at the time of bullet impact has also shown to affect the animal's reaction to the hit. The state of the respiratory and circulatory systems are the two big ones.

Thats definitely something to ponder, I have often wondered how sometimes we can just absolutely hammer a goose round after round and it flies off another 300 yards before it folds or sails away slowly before coming down and landing and once its recovered and cleaned it is full of holes in the areas of the vitals and others are down and dead with a pellet in an area that would for all intent leave you thinking it should have continued flying for days?My Grandfather told so many stories of moose and deer he took with his 348 that just keeled right over on the spot as though their legs had been cut out from under them, he never attributed it 100% to the rifle-calibre but he sure loved that rifle after he purchased it in '58 or '59 and started putting it to use.