Energy or bullet diameter most important?

[Canadian Bushman]

I think energy is a nice number to look at as part of the total equation to determine if you are using enough "gun". Energy alone is an arbitrary number.

Energy "dump" into an animal is a physics wives tale. To have a bullet end up in the far side hide would mean that it has to slow down enough while inside the animal to stop just before exiting. The slower that bullet gets while inside the animal the less damage it does. To predictably have a bullet stop on the far side you would have to determine the impact velocity needed and never have that velocity vary due to different distance of shot. Think about the total energy of a bullet hitting the animal with no penetration. The animal would literally walk away with no ill effect. I can shoot a steel target with huge energy and it will cause it to swing a few inches. I can push that same target with one finger and create a larger swing. There is no such thing as knock down power. Myth Busters did an episode on that very subject and proved that it does not exist.

Bullets kill by tearing soft tissue in order to cause hemorrhage or by interrupting the central nervous system via the brain or spinal cord. The cns stops by loss of blood or physical damage.

Simply put the best most predictable way to kill an animal is to put a large permanent wound channel completely through the animals vital organs.

In my opinion the bigger displacement is more important in the total equation.

Steve

I respectfully disagree

 

[wilkup]

... Energy "dump" into an animal is a physics wives tale. To have a bullet end up in the far side hide would mean that it has to slow down enough while inside the animal to stop just before exiting. The slower that bullet gets while inside the animal the less damage it does. To predictably have a bullet stop on the far side you would have to determine the impact velocity needed and never have that velocity vary due to different distance of shot...
Steve

Respectfully, this is only part of the equation. Bullet velocity and diameter make up a portion of what you're trying to describe. Where this gets muddied is when bullet construction is introduced. For instance, the solid copper options that are available verses traditional bonded core options, but then there's also the Bergers that are designed to "grenade" inside the animal and destroy the insides. I don't believe anyone would argue the efficiency that any of these bullet options kill with. It just depends on the game you're attempting to hunt and matching it to the correct bullet. =) All that to say, it is possible to expend "all energy" inside the animal without pass through, but sometimes that's not the best way to kill the hunted animal. I like 2 holes on bears, but elk and deer I'm happy with Bergers blending things internally.

 

[RockyMtnMT]

I respectfully disagree

Respectfully say why. Think hard about why and be ready to prove it.

Steve

 

[RockyMtnMT]

This is very worth discussing. Minus campfire lore.

Steve

 

[Canadian Bushman]

Respectfully say why. Think hard about why and be ready to prove it.

Steve

How can a bullet Dumping energy into an animal be an old wives tale? What happens to the energy a bullet has, when it hits an animal and does not exit?

How could you possibly imagine 2000ft/lbs of force hitting an animal in a 1/4" size area and neither penetrating or hurting the animal? How is this even a possible scenario?

What happens to the bullet when it hits the steel plate and barely causes it to swing? Where has the energy gone? What happens to the ground in front of a target? What determines whether the bullet deflects or penetrates the steel?

Comparing a bullet hitting steel and pushing it with your finger is not a fair comparison of a bullet striking an animal. For one, the properties of the targets are vastly different. Secondly the amount of force and rate of application are vastly different. Surely your deer dont go rolling across the ground when they are shot?

I do agree with you that damage to the animals internal organs is what kills them. I also agree that its usually the bullet or bullet fragments that cause this damage. I agree this usually happens when there is a large displacement ( of what you didnt say ) of the bullets velocity, energy, and even materials. How is this not considered and energy dump?

 

[RockyMtnMT]

It is not the energy that causes the soft tissue to move from it's current position to a new position. It is caused by the velocity and shape of the object moving through the tissue. You can move an object through an animal slowly with huge energy and do fairly little in damage. You can also hit it with an object moving very fast with very little energy and do very little damage. So energy is definitely part of the equation. It is not the release of the energy that does the damage. If a highly frangible bullet that "dumps" all of its energy in the 1st inch and stops the "energy" is meaningless.

So in the end the flatter the front of the projectile and the faster it is traveling the larger the permanent wound channel. Permanent part means, as the tissue is pushed out of the way and springs back, how much can not return to original form. This would be due to tearing. The torn tissue then bleeds to turn off the CNS.

Steve

 

[RockyMtnMT]

Here is a link to a physics study of this very subject. It is difficult dry reading, but quite interesting if you are really wanting to know how it works. I read the whole thing a few years ago and it took me a couple of full days of reading. Very good read.

Terminal Ballistics

Steve

 

[Canadian Bushman]

It is not the energy that causes the soft tissue to move from it's current position to a new position. It is caused by the velocity and shape of the object moving through the tissue.

So if we had two equal shaped fragments of a bullet. One made from plastic and one from lead, moving at the same speed, they will do equal damage?

You can move an object through an animal slowly with huge energy and do fairly little in damage. You can also hit it with an object moving very fast with very little energy and do very little damage.

I agree
But at the same speed is where the comparison becomes fuzzy.

So energy is definitely part of the equation. It is not the release of the energy that does the damage. If a highly frangible bullet that "dumps" all of its energy in the 1st inch and stops the "energy" is meaningless.

Luckily for us, this scenario is extremely unlikely.

So in the end the flatter the front of the projectile and the faster it is traveling the larger the permanent wound channel. Permanent part means, as the tissue is pushed out of the way and springs back, how much can not return to original form. This would be due to tearing. The torn tissue then bleeds to turn off the CNS.
Steve

What about bullets that rapidly expand or fragment? Dont they create a good size wound channel? What would be a good way to describe the possible distinction between the explosive potential of two different sized bullets leaving at similar speeds at a variety or ranges and conditions?

 

[RockyMtnMT]

Explosive bullets are unreliable as to how far they will penetrate. It all depends on the velocity of impact. A bullet that will reliably make full penetration is more likely to have consistent killing results.

Steve

 

[Canadian Bushman]

Explosive bullets are unreliable as to how far they will penetrate. It all depends on the velocity of impact. A bullet that will reliably make full penetration is more likely to have consistent killing results.

Steve

I strongly disagree.
My experience has shown them to be just as, if not more consistent than bonded and solid bullets.

I suppose by now it is safe to assume you will not be addressing any of my questions?

 

[Broz]

Larger heaver bullets can transfer more energy to the game and have more momentum that Helps penetrate thicker skin and bodies.

A lighter smaller bullet may have the same energy but does not have the ability to transfer all of its energy unless it is stopped buy the game hunted.

In many cases cartridges like the 7 Rem mag will pass completely through a deer sized animal without transferring all of its energy allowing the animal to run long distances before collapsing, but a less powerful cartridge like the 7/08 will knock them off there feet with far less potential energy and transfer most if not all of its energy to the game.

So to answer your question , It is a combination of both, based on the game you will be hunting. Ideally, you want the bullet to end up under the skin on the opposite side (It delivered all of its energy to the game).

J E CUSTOM

Hard to beat .308/.338 cal holes in game !

+1
Velocity at impact also comes into play.
Like so many things in life, its not as simple as one or the other.

^^^^^^ THIS^^^^^^^^THIS^^^^^^^^^^^^^& THIS^^^^^^^^^^^^^^^
After being there for the taking of over 70 elk last season alone. What JE describes is what the bullets we use do a large percentage of the time, inside the distance limits of the OP's post.

( Quote JE Custon) "Ideally, you want the bullet to end up under the skin on the opposite side (It delivered all of its energy to the game). (UnQuote)"

These animals drop in their tracks, or within a short stones throw of where they were shot.

The numbers of sample data I have seen from the inside of elk makes it hard for me to not believe this is gospel. When they never leave the field of view through your scope, two holes in the carcass become irrelevant.

Jeff

 

[wilkup]

Explosive bullets are unreliable as to how far they will penetrate. It all depends on the velocity of impact. A bullet that will reliably make full penetration is more likely to have consistent killing results.

Steve

This is excellent dialogue and a wonderful opportunity to learn new things; exactly why I value this forum! =)
Would you consider the Berger variety of bullets to be "explosive"? If so, I would disagree completely with the assertion of their unreliability. In my experience and many other, they kill with authority and very effectively.

 

[FEENIX]

Let's say you are hunting for elk sized and smaller game and are targeting 750 yards or less. Would you say it would be more important for lethal, ethical kill to be the size of the bullet (just an example 30 caliber vs 25 caliber) or the ballistic energy the bullet gives out to that range (just an example 1200 vs 1800 lbs regardless of bullet size)?

I am trying to leave this somewhat open ended to avoid only comments from those who love a certain caliber, but I am considering a future rifle and am hopeful with plenty of practice I could possible do what I listed above. So many calibers out there, I just want to start with the right base and get proficient from there.

Thanks in advance.

Try these, it should give you a general idea about your query ...

HITS calculator - Hornady Manufacturing, Inc

Taylor KO Calculator | Energy | Momentum | Bullet

 

[Greyfox]

This is s discussion that has been going on for well over a century. I think John Taylor's Knock "Knick Out Value" concept which assumes a solid bullet still has relavance today.

(Bullet weight X Bullet Diameter X Velocity) / 7000 = Knock Out Value

He believed ithat a value of at least 60 was needed to knock out an elephant with a properly placed bullet to the head. I like to use this formula using the velocity "at the target". A value of "10" for deer sized game and "15" for elk sized game. While it doesn't account for bullet expansion I think it does account for sufficient penetration energy to reach and damage the vital organs and has served me well as a guideline. The formula gives credence to velocity, bullet weight, and diameter to effectively take game. IMO.

For example, 1000 yards is my max range for deer with my 6.5x284. (1850FPS X .264 X 142) / 7000= 9.9 Knock Out Value.
My 300WM load produces a value of 15 at 1000 yards. (1800FPS X .308 X .210) / 7000.