bullet energy limit

[tacomHQ]

For the crazy end...
Velocity and mass, in the end, is the final function.
How many people have actually tested "the end". I love the battleship analogy earlier and indeed the 45cal weapons at an extreme range were more destructive than the higher velocity 50cal weapons. Steeper remaining angle and gravity.
This past year our optics were used (required) to make a 6013yd shot (later 7070yds). With that, the observations of that shot:
Flight time 17sec
Fully dented (1/4 inch deep) a 1/8 mild steel plate
Striking angle greater than 30deg (a glancing hit and therefore a dent)
Enough energy was imparted to the solid projectile to remove over 100gr of weight from the projectile.
Flight time was long enough to decay the spin of the projectile by 30% if not more.
Ground penetration was still 8-12". With the oddity that all of the retrieved projectiles (15 units) flipped inside the ground- talk about a wound channel.
Estimated velocity was 600ft/sec. or around 409mph...
Are the projectiles wobbling? Yes.
Does the wobble change projectile to projectile? Yes.
Quite simply you might be amazed how much a projectile can "wobble" coming out of the muzzle - amazing what failures can yield...
Would they kill something - absolutely.
For those who are going to scoff at the absurdity of such a shot- so was a 2000yd shot 20yrs ago. Now cold bore +2 follow up impacts now occur beyond that 2000yd figure in competition. Sniper kills hung around 2100yds for years then jumped to 2+ miles. Absurdity today ..?

 

[dfanonymous]

I won't assume what BG means, but IMO, when "energy" is dismissed as "misunderstood, meaningless, etc" in these threads, it is just as ludicrous as dismissing bullet construction/design. Energy is one important variable to assess the ability to do work (tear tissue in this case). It's akin to saying "Bah! Horsepower is meaningless in a car race! It's speed that matters!"


I agree there isn't a great deal clarity in the testing that's been done. That's because it's a very difficult test. Lots of variables. That being said, there's lots of good information out there from science (application and experiment), and energy wouldn't come up so often if it wasn't an important metric.

To my car analogy. "Speed wins races, and it takes traction, power (work and time), and good driving to get speed".

IMO, for this topic, that's "Devastating wound channels drop animals quickly, and it takes bullet design, energy (speed and mass), and good shooting to get devastating wound channels".

Skill is beyond this discussion, but I think the other two are roughly of equal importance.

To my point, it's complicated in that everything is involved to include bullet design and construction, as well as anatomy, physiology, physics, ballistics to include external and terminal. To that end, I default to wildrose's points he makes, due to reliable ways of concluding antidotal data. However, again it's over simplifying it by KE alone, including your understanding of mass x velocity, which is correct but not the actual formula. Momentum is a byproduct of this. There is a reason why a 20mm cannon will kill you, even if shot in the clavicle, or hip, or what would normally be considered a disabling shot in small arms. A big part IS the KE for sure. Another is the momentum transferred to the target. Momentum that normally would have the weapon be mounted to something as momentum and recoil have correlation. To your car analogy, I'd still rather get hit by a baseball at 80 mph then a heavy bowling ball at 40 mph. I'd rather get hit by a car at 40 mph then a semi at 20. I hate car analogies past that, it's the same as guns, because while you might need speed in a race car, you need torque, traction and sometimes momentum plus skill in a 4x4 rock crawler. All are vehicles, but both do different things using different emphasis on measured forces to get from point A to B.

Some people like the speed and capacity of a 9mm but a .45 still has more momentum even though a 9mm can replicate its KE, and practically, and statistically, they both suck at killing based on numbers alone, thus making shot placement, and bullet design and function more important either way.

So, it's my personal opinion that to quantify a specific number to apply to lethality is difficult without considering all other things, not just KE alone, especially when in most ballistic gel test bone is not a factor, let alone different densities for different species, across a vast spectrum of variables. A fast small bullet that would work very well on a human or deer may not have the necessary momentum to enter vitals in another species. To much momentum will cause over penetration, and maintain its energy not dumping at least 50% but ideally 90-100% of its energy but still hits vitals. I believe absolute energy then needs to be determined at that point. Since archery has less overall KE on a target, penetration is very much relied upon, and the topic goes round and round.

 

[birdiemc]

For the crazy end...
Velocity and mass, in the end, is the final function.
How many people have actually tested "the end". I love the battleship analogy earlier and indeed the 45cal weapons at an extreme range were more destructive than the higher velocity 50cal weapons. Steeper remaining angle and gravity.
This past year our optics were used (required) to make a 6013yd shot (later 7070yds). With that, the observations of that shot:
Flight time 17sec
Fully dented (1/4 inch deep) a 1/8 mild steel plate
Striking angle greater than 30deg (a glancing hit and therefore a dent)
Enough energy was imparted to the solid projectile to remove over 100gr of weight from the projectile.
Flight time was long enough to decay the spin of the projectile by 30% if not more.
Ground penetration was still 8-12". With the oddity that all of the retrieved projectiles (15 units) flipped inside the ground- talk about a wound channel.
Estimated velocity was 600ft/sec. or around 409mph...
Are the projectiles wobbling? Yes.
Does the wobble change projectile to projectile? Yes.
Quite simply you might be amazed how much a projectile can "wobble" coming out of the muzzle - amazing what failures can yield...
Would they kill something - absolutely.
For those who are going to scoff at the absurdity of such a shot- so was a 2000yd shot 20yrs ago. Now cold bore +2 follow up impacts now occur beyond that 2000yd figure in competition. Sniper kills hung around 2100yds for years then jumped to 2+ miles. Absurdity today ..?

I just did a quick search to see if there's documented force required to penetrate flesh...very quick search but I got 3 interesting results.
One from the Univeristy of Utah "The speed at which a projectile must travel to penetrate skin is 163 fps and to break bone is 213 fps" but they dont specify a particular bullet weight so those numbers could be deemed meaningless.
A stab wound only requires 10-20 newtons, so under 5 ftlbs
It takes 4000 newtons, roughly 900 ftlbs to break a human femur.
Again very quick and not conclusive web search, but interesting numbers.
I have no idea what round was fired in the example above, but can only assume it's going to be greater than 200gr, for that distance with retained velocity of 600fps at impact I would guess we're talking about a .50 maybe?
But using a 240 gr bullet, it would have 192 ftlbs at impact so by the numbers I found on the web, enough to penetrate skin easily, but not enough to bust up bones. So based on energy alone, that's a good shot at a terrorist, maybe not so good on something we dont want to risk just injuring and inducing lots of pain and suffering and perhaps a slow and painful long drawn out death.
But throw in the number 2400 newtons or 541 ftlbs that an amateur boxer packs in his punch, obviously without penetrating the skin, and maybe what folks are saying about pure KE not being enough for determining bullet effectiveness is true.

 

[35 Whelen]

I like all the responses to this. All are very good and informative. I all so like that every one is keeping a good attitude. Keep it up I'm enjoying this.

 

[BallisticsGuy]

I disagree.

I talk about energy in projectiles all the time, and I certainly have a pretty extensive education in science... More relevantly, MANY accomplished hunters do the same.

Why? Because it is a good metric of 2 quantities required for creating wounds. Mass and velocity. In other words, it can summarize two variables in a relatively easy to compare number.

Energy is not just mass and velocity. The velocity is squared for a specific reason. That would be fine if wounding was mathematically related to the square of the velocity but it's not. It's literally exactly the wrong thing to use. Energy gives us a value of the ability for work to be done but it doesn't directly translate to wounding effectiveness or target defeat (penetration) effectiveness. If there's no reliable method of translation of energy to wounding effectiveness or penetration then you're using the wrong point of comparison because you can't compare anything but energy numbers.

if 1a cannot be shown via any equation to always be equal to 2b then there is no comparability between 1a and 2b. Q.E.D.

 

[sturner]

Tag

 

[entoptics]

...That would be fine if wounding was mathematically related to the square of the velocity but it's not...Energy gives us a value of the ability for work to be done but it doesn't directly translate to wounding effectiveness or target defeat (penetration) effectiveness. If there's no reliable method of translation of energy to wounding effectiveness or penetration then you're using the wrong point of comparison because you can't compare anything but energy numbers.

You seem to be arguing against a straw man. I don't think anyone is implying there's a rigorous mathematical formula of "A x Energy = B x Death". Frankly, I don't think there's any equation that perfectly predicts terminal performance. I suppose there could be some misguided folks that think that, but that's not what I'm seeing in this thread.

if 1a cannot be shown via any equation to always be equal to 2b then there is no comparability between 1a and 2b. Q.E.D.

Q.E.D...? That's a bit bold...

It's literally exactly the wrong thing to use.

...So...What is the right thing to use then?

 

[tacomHQ]

The round in question was a .416 shooting a 550gr Cutting Edge bullet at 3000fps.
To further clarify: different bullet manufacturers had different "wobble" traits not bullet to bullet.
I also totally agree that the final question is total energy imparted into the object. Pencil holing has an effect - but "when" can be an issue. Look up the devastating effect of plastic/teflon bullets on an animal at close range. Their design is focuses on room incursion- all energy left in the object. No exit. Massive wounds create an instant shock to the nervous system that is not easily overcome by adrenalin.
In our case, the actual bullet that did hit the target actually still penetrated
the ground. The observation that the bullet flipped around 180 degrees would indicate all of the energy was dissapated in a wound, creating a mechanical wound channel at least 1 3/8" in size-- mechanical carnage.
The David Tubb nose ring ( which can be added to target bullets) has an unexpected impact (BC was the first goal) of dramatically improving the impact effect on an animal. The hydraulic effect is pretty devastating as the bullet nose collapses upon itself with little required resistance.

 

[birdiemc]

The round in question was a .416 shooting a 550gr Cutting Edge bullet at 3000fps.

That puts the energy up to 440ftlbs...again, I would lob that at terrorists all day long, but I wouldn't want to go after the trophy of a lifetime with something like that. Specifically talking about the energy on impact.
Back to the original subject, I think most folks know from experience or second hand that it's not wise to hunt elk with a .22 and gophers with a .338 might be overkill. And it all depends on energy combined with bullet design but mostly on shooter ability.

 

[J E Custom]

I think the Taylor Knock out values were for the beginner to the average hunter as a guide for him to use with limited access to ballistic charts and bullet designs. It is for general use and not for a well versed shooter/hunter in the ballistics of every bullet that may be able to take full advantage of a lesser cartridge because of his understanding of the total process.

It also assumes that the average shooter may not make the perfect shot every time.
he may also not know what his rifle cartridge combination is capable of. So if these values are used buy the average hunter, They will probably keep him out of trouble most of the time.

J E CUSTOM

 

[WildRose]

You seem to be arguing against a straw man. I don't think anyone is implying there's a rigorous mathematical formula of "A x Energy = B x Death". Frankly, I don't think there's any equation that perfectly predicts terminal performance. I suppose there could be some misguided folks that think that, but that's not what I'm seeing in this thread.


Q.E.D...? That's a bit bold...


...So...What is the right thing to use then?

It gives us the measure of the Kinetic energy on impact which is very valuable. It doesn't tell us the full story because there are so many other variables relating to bullet type and construction, strike location, thickness of hide, muscle, bone as well as hardness of bone etc.

There is no one equation that can begin to cover it all.

 

[BallisticsGuy]

It gives us the measure of the Kinetic energy on impact which is very valuable. It doesn't tell us the full story because there are so many other variables relating to bullet type and construction, strike location, thickness of hide, muscle, bone as well as hardness of bone etc.

There is no one equation that can begin to cover it all.

This.

 

[KurtB]

As long as I am getting 2000 fps or so when the bullet arrives, I am confident the bullets I am using will destroy enough tissue to kill what I am shooting at. I never consider energy in the equation.

 

[WildRose]

As long as I am getting 2000 fps or so when the bullet arrives, I am confident the bullets I am using will destroy enough tissue to kill what I am shooting at. I never consider energy in the equation.

You actually are because that velocity limit exists because of the energy needed to get the bullet to perform as designed.