I have done a stopping power test last week..!

I put sand into a barrel that take 25 l. The weight was around 40 kg. And I put it up on a chair and then I shoot it with my .460 wby with 500 grain Hornady SP bullet at 2600 f/s. From 40 yards. And when the shoot went off the barrel had move down from the shair and was on the ground 2 yards away. I dont know if it prove anything but it was fun. Oh i forget the say that I shoot the same barrel with my 12 guage shotgun and with a 420 grain slug before I shoot it with my .460 And the barrel did not move from the chair. I did that just to see if the swedish "vapen tidningen" was right in this " The bigger diameter a bullet have the more stopping power it have" And a slug in a shotgun with caliber .12 have a diameter of 18 mm and the .460 11,6 mm. And they also said that a caliber with more foot pounds energy will not move the target longer if it dont have a bigger diameter than the other caliber with less foot pounds energy but with a bigger diameter.

I dont know if this prove any thing about "STOPPING POWER" What do you think guys.... // Overkill

Sorry Overkill, your just pissin in the wind..

Proves nothing.

Overkill...what "STOPS" critters and people alike is destroying vital organs and causing system failure...not theoretical energy figures. Hit anything where it ought to be hit and with a bullet that does what it's supposed to do and it's gonna die.

It's what our airforce calls the "Golden BB Syndrome." Put that BB in the right place and you've got "STOPPING POWER." But you can put a brick in the wrong place and all you've got is a dent..or a pissed off dangerous animal looking to settle a score with you.

This interesting topic, I agree with the hitting the right parts thing, but doesnt caliber and speed matter? And I asked this before I think, but there are shock wave effects are there not? Use a rail gun and small palstic projectile anywhere in torso, body is going to do what this watermelon did wouldn't it?

The below image is watermelon, 2nd frame at 15 frames/second after 454 Casull hit, width is at least 8 ft, maybe a couple more. A 50 cal BMG just punches hole, but is moving fast, pointy bullet? I am trying to find someone that can tell me the determining factor of what explodes vs punches hole? A 45 acp and a 45 Colt just punch holes also.
I am new and haven't seen any images posted, if this is annoying please tell me, I will edit out. But if you see, ya gotta say it is kinda pretty.



[ 07-18-2002, 01:14: Message edited by: deranged-havoc-aficionado ]

Overkill, when are you going to do your test with a 300 to 800 kg barrel swinging toward you? This would be the most interesting test I think. The low end would be like a bear, the 800 kg mass more like a buffalo. You would need a very stout frame to keep it swinging smoothly and to make sure that it could not come loose and really endanger the shooter. If you do this, you simply must video the action.

DHA, the force created by the dynamic pressure, which is what causes that splash effect, is related to nose shape, presented area and velocity. Imagine the drag effect of a bullet in flight and you can conceive the kinds of factors that increase the "splashiness" of a bullet. The basic equation is: Force = density of the target / 2 x velocity^2 x presented area x form factor coefficient. That last coefficient is empirically determined, much like a ballistic coefficient. The big point is that the dynamic pressure is related to velocity squared, so it increases quickly as velocity goes up, which is why you see a huge difference in the effect created by a .454 Casull as compared with a .45 ACP even though both bullets have similar form factors and presented areas. I have a graph that gives the dynamic pressure in psi for projectile velocities through water on my website at: http://www.mindspring.com/~ulfhere/ballistics/wounding.html

The 500 grain Hornady SP lost all weight when I shoot in the barrel. So I think that if I use a solid bullet then it will knock it down faster.

Harald..!

Do you remeber Kent in IA? He did a test with a 300 kg barrel and it was knocked down. even with a 440 grainer...! I am still thinking of to do that test that you ment. Swing a 500 kg barrel at me No. But it would be fun to see if a 200 l barrel full with sand will be knocked down with my .460 the weight would be around 300 kg. But I will wait with that test. And then if I ever do that test I will use a solid bullet so that maximum energy punch the barrel.

Overkill, a softpoint will hit harder than a solid, assuming the solid penetrates deeper. Forget the teetering barrels, I want to see somebody try to "stop" (i.e., arrest the forward progress of) a mass approaching that of a charging dangerous beastie. I would even settle for a first test that just showed how much swing you got from a freely hanging still mass of at least 300 kg. I predict it will be unimpressive. Be sure to then have a guy run up and kick the drum for comparison.

Harald..!

Yeah a soft point will hit harder. If it stay together and not lose much weight. But if it do like the 500 grain Hornady bullet I shoot into sand then a solid will hit harder. Because the Hornady explod and the weight after that was maybe 15-20%. But I am sure that a Swift or woodleigh will stay together.

A test like that would be fun. To see a mass coming at you and then shoot it and see if it stops at all.

Am I missing something here? If you shoot any kind of bullet into a drum full of sand, if the bullet doesn't exit, you done put 100% of the energy into the drum.
If you have a 300 kg drum swinging in some way coming at you, you ain't gonna stop with any rifle, try to stop it yourself. I think you might be thrown a bit. That is what the recoil of a rifle that would stop it would have, and a bit quicker>>more powerful. I hope you don't believe the westerns with the guy being thrown backwards by a bullet. Surely I am misreading something if people on this board would think that?
Now, a hanging drum, measuring how far it swung after a hit, that would be a trivial calculation, no need to test, but would be fun to do Now, I am not saying anything if the bullet exited, whole nuther story to calculate.
rob

[ 07-20-2002, 10:10: Message edited by: deranged-havoc-aficionado ]

Harald and all guys..!

I have been thinking of the "stopping power" test that Kent in IA have done. He shoot at a barrel the weight 600 pounds ful with blood and dead animals. And he said that he could not have push it down easy. And you guys say that a bullet cant have more push energy than the recoil of the rifle. But I dont think that the recoil could have knock the barrel down. But when he shoot the barrel it was knocked down. And he only used the short 440 grain woodleigh bullets in his 500 jeffery. A 570 grain bullet would have hit much harder. And when I shoot the little barrel 25 l (40 kg) it was knocked 1 m away from the table. And the recoil from my .460 wby could not have done that. So a test with a barrel with a weight of at least 200 kg that is rolling at you and then shoot it with a big bore and see if it stops would be fun. And Harald..! The swing thing that you ment would not stop because it would have much more energy and speed than any animal. So that is not any good test

Gentlemen,

All these numbers are absolutely meaningless when it comes to shooting a live animal.

Here is what I mean.

Imagine an impala, which weighs - I am going to be very generous here - 150 pounds max.

This impala is standing looking straight at you, at a distance of 100 yards.

You shoot him in the center of the chest with a 300 grain bullet that started of at 3140 fps - that is 6,570 foot pounds of energy.

The bullet does not exit from him, so he absorbed all that energy.

Accotrding to Hollywood, that impala would be thrown up 10 feet and land 20 yards from where he was hit!

In actual fact, he just drops in his tracks.

Now, would someone please explain to me what happened to all that energy!

You want to stop an animal, hit him in the brain.

Saeed..!

Think about if the same impala would be hit with a .700 BMG IMPROVED 1000 grain bullet at 3000 f/s will give 20 000 foot pounds of energy. It feels to me that the impala is going to be knocked down. I have been thinking about that the old african hunters used a 4-bore as a "stopping rifle" why? and why did they say "stopping rifle"

Why are you going to throw the animal around. Isn�t the most important that the animal will die fast??

Saeed.

quote:

---

Now, would someone please explain to me what happened to all that energy!

---

Well if my memory serves me right, we learned something in school a while back. (Some 15 years ago)

Energy does not vanish into nothing, it changes form.

So my question is: If all that energy is left in the animal, why is it stone dead? Shouldn't it be running around in a zillion miles/hour?????

Magnar

All that energy beyond that which did any mechanical work just gets dissipated as heat within the animal when the bullet comes to rest without exiting.

Assume the the 150 pound critter absorbs 6000 foot pounds of energy. To simplify the calculation assume the critter is just 150 lbs of water. By how much does the impala's temperature rise?

Rob,
Very true. The rifle chews slowly on the shooter's shoulder but the bullet bites the target quick and hard. Most of the kinetic energy of the bullet (or more correctly momentum) comes back at the shooter in recoil, but the rifle being much heavier, slower moving, and less pointy than the bullet, it doesn't hurt the shooter as much as the critter.

Hollywood (and Overkill ) just don't understand the concept.

BTW, 6,000 ft.lbs. of KE = 8,136 Joules

1 BTU = 1,055 J

1 BTU raises the temperature of 1 pound of water 1 degree F.

So, 6,000 ft.lbs. will raise the temperature of 150 lbs. of antelope water by only 0.05 degrees F.

Like shooting a bullet into a swimming pool, the bullet comes to rest with barely a ripple, and barely a change in the temperature of the water.

[ 07-21-2002, 06:11: Message edited by: DaggaRon ]

More for Overkill:

1 Joule = 1.356 ft.lbs.

One "Nitro Express Stopping Unit" = 5000 ft.lbs.

1 NESU = 3.494 BTU

Cape buffalo water content = 1000 lbs.

1 NESU will raise the buffalo's rectal temperature by LESS THAN 0.003494 degrees F, kill the buffalo, and not budge it a millimeter if the proper bullet and proper bullet placement are used.

Just some food for thought.

How many bullets will it take to cook the buffalo to medium rare?

Hey DaggaRon,
The kinetic vs heat ratio got me thinking, that is where the momentum thing comes in, or is my physics too long ago? Calculate the backwards movement of target, use that to determine it's momentum, subtract energy required to give that momentum to bullet, voila, it's the heat. Or I am making a complete ass of myself. It's not a rare thing.

OR , do you have to measure the momentum of target? I am leaning towards being able to calculate, but, you got bullet direction changes, etc? The gray matter just ain�t up to it anymore, a few too many gallons of vodka and other niceties.
rob the less than adequate physicist

Gee, this lack of visible effects on the target critter must have something to do with the elasticity of tissues and the containing sack of skin around the elastic tissues within. Of course the actual water content and specific heat of the buffalo are simplifying assumptions, but it does illustrate what is actually going on.

Saeed is right about the impossibility of numbers applications to game animals. It is just to complicated for any mathematical models to explain, partly because it changes from moment to moment within the same critter. Always varying and unpredictable.

Rob,
You are getting too complicated for me. That is another reason why the numbers are impractical with game animals. They won't stand still for measurements such as rectal temperatures before and after being shot. Sometimes they run off and work up more heat!

Hi DaggaRon
You seem to have retained your physics much better than my sorry ass, I have been on another thread about the trebuchet, a sorta catapult/sling hybrid, very cool. The ones I saw in recent PBS show could hurl 250 lb stone 200+ yards. Can you calculate the energy of these suckers? Just curious, ya ain't got velocity figures, so got to back out of weight/distance, and god knows what else enters.
Thanks
rob the way too curious Neanderthal reject

DaggaRon
You mean yaou ain't never done a rectal exam on a rhino? I thought everybody had
This has now officially gotten to silly zone.
I keep writing and missing responses, pardon, it's rare for me to be posting sorta in 'real time', that is more chatting, which I hate, you can't edit out any stupidities, which I am very good at.
rob the leader into sillyness

Rob,
Any thread that Overkill posts about "Knock Down" is bound to degenerate into silliness. I couldn't resist this time, my bad. I will try to be stronger hence forth, after just one more indulgence:

Your catapult KE would require a ballistic coefficient of the rock, time of flight, or something more to back into the departure velocity of the rock, or some chronograph data/film analysis, etc.

Just for a sample calculation assume 200 fps.

That is just over 155,000 ft.lbs., only about 31 NESU.

Not very impressive for 40 men to be required. 40 men each firing 1 NESU could do better.

However a rock of 31 NESU might budge the buffalo, probably kill it too. Still wouldn't cook it to medium rare though.

Enough of this for now!

Norbert,
Whomp is measured in BS units. The Bwana Saeed Index ranks cartridges by units of BS which may also be called BSI. Thanks for bringing up this important point.

Maybe the next frontier in lethality indices will be a rating of BTU's delivered to mass of water in the critter. Of course weighting factors for the sectional density and cross sectional area of the BTU's, as well as a form factor, will have to be factored in.

This might be better than the Ed Matunas "Optimum Game Weight" recommendations (OGW).

The Optimum Water (OW!) value for a given cartridge might prove to be another useful parlor game. Useful for what I do not know.

To continue: Muzzle whomp of a rifle is a concept borrowed from Ray Atkinson, the term "whomp" is an Atkinsonism.

BSI is a an improved Taylor K.O. value arrived at by factoring in a sectional density term and correcting for unitary consistency of bullet diameter (inches) and velocity (feet per second), by dividing by 12, which Taylor never bothered to do, though he did bother to convert grains to pounds by dividing by 7000.

Voila! BSI!

Now to continue seriously:

Norbert has brought up an obviously neglected aspect.

Overkill is considering constructing a ballistic pendulum. Obviously the results of such were used every day over a century ago to calculate muzzle velocities of the day.

I have read of such things but can't recall what was measured in the reaction of the pendulum, the velocity of the down range motion of the struck pendulum? The initial amplitude of the swing? Distance X traveled in Y time? A ruler and a stop watch? And then using the principle of conservation of momentum, mv of bullet = mv of pendulum?

What were the calculations involved, and what were the pendulums made of? Were they logs hanging on chains under the old oak tree?

[ 07-21-2002, 06:36: Message edited by: DaggaRon ]

RAB,

The pendulum would have had some sort of a slide so that the height it rose to could be measured and from measurement the velocity of the pendulum could be calulated.

Then probably stuff like V^ = U^ + 2AS where V is final velocity, U is initial velocity (=0)and A is accelaration of gravivity and S is the height and of course the pendulum momentum will equal bullet momentum.

How does the 460 by go for BS factor. Does in line feeding mean the BS factor can be less for the job at hand

Mike

Mike,
Thanks. After I posted the above I remembered that P. O. Ackley's _Handbook for Shooters & Reloaders_, Vol. 1, pages 191-195, has a chapter entitled "A Simple Chronograph which can be made by the Individual Shooter for His Own Use."

This shows the calculations and shortcuts to get velocity, as well as diagramatic plans for constructing the pendulum.

The BSI of the 460 WBY is 246 with a 500 grain bullet at 2600 fps. Compare this to the 375 H&H with the old low ball load of 300 grains at 2450 fps, which has a BSI of 100 even.

The 460 Wby does indeed have a lot of BS, but this is not at all affected by in-line versus staggered stack magaxine, unfortunately.

Yeah it is more important to kill the animal fast. But is there anything that is "stopping power" then..?? and why is there "Taylors knock out value"

Look, stopping power ain't got anything to do with 'stopping' the animal, just how quick you kill it, which does tend to 'stop' it, but if you kill a chargeing elephant on a frozen lake, you better get the hell out of the way . I have no idea if an elephant has ever been on a frozen lake, I doubt it, just an analogy, but would love to see overkill in that situation, give him a quad 50 cal, and see how fast he decides to abandon his weapon. Don't mean as an insult, just humerous thought that popped into head, can't help it, been pretty warped by strange life.
rob the guy who usually sees pink elephants

DHA...!

Yeah I know that "stopping power" is to kill the animal fast. But in the sweidsh magazine "vapen tidningen" they have done tests on sand bags and other similar things. And they say that "stopping power" is to stop the animal. If not at once but it slow it down a bit.

But one thing makes me GS Custom bullet company say that their 270 grain .375 cal bullet will do more damage to a animal than a .458 cal soft point will do. I dont know why?

So if "stopping power" is not to stop the animal just to kill it fast. Then the only way is to use a caliber that do as much damage as possible. For moose and bears will a 300 grainer at 3200 f/s from my .460 wby be best. It will be like a little bomb grenade. Or a 750 grain woodleigh SP bullet from a .577 TYRANNOSAUR at 2750 f/s because the woodleigh 750 grain SP bullet is made for cal .577 NE velocitys. around 2000 f/s i think.

Yeah I know that I miss some thing.

On big animals like buffalo and elephant and similar game. Then bullets like these that i ment is not going to penetrate any far in a big buff. Then it have to be a hard and heavy bullet so that it can go handle big bones. But I was just talking about angry bears and moose.

But you have not been here so long so you dont remeber Kent in IA:s "stopping power" test.
He used a big barrel ful with blood and dead animals i think and the weight of the barrel was around 600 pounds. And he put it up on 4 legs and then he shoot it with a .500 jeffery with 440 grain SP bullet. And the whole barrel was knocked down. I dont know why, if there is nothing that can stop or knock down things.

//Overkill

Hi overkill,
One thing I really think you need to grasp is the difference between energy and power, you might already, but it doesn't seem so.

If you shoot the barrel with a blow gun loaded with a pea(a pea shooter) you can impart to the barrel the same energy as the 500 jeffrey, you just gonna have to shoot a lota peas. The jeffrey imparts that much 'energy' almost instantly, that is a whole lotta power, energy over time is power. I used to work with laser that had very enemic energy, but it was in a pulse of 20 nano-seconds, it would 'pop' if it hit your retina, blood would cloud your vision, it would blind at well over two miles.

Please see what I said about pushing on you for an hour vs having that much energy imparted on you in 10 nanoseconds-see watermelon pic, it might be a lot worse than that.

I don't know much about what will take down an animal, obviously many variables, obviously, put a projectile in the right place. You could kill an elephant with a 22 if you got it perfectly placed through the eye socket into the brain, might take it awhile to die. Or run into it with my V10 Ram at 100 miles/hr, hope the air bag works. I have just been talking physics, which ALWAYS, and I mean ALWAYS, YOU CAN'T EVER EVER ESCAPE THIS, governs everything, even psychology at a very deep level, chaos theory is a part of physics. Bullet trajectory in body is too complex to ever predict if not obvious through some soft tissue... You are almost getting to the level of chaos theory-complex-non-linear systems. Break at pool, perfectly elastic balls, no pockets, etc. etc is impossible to predict what will be happening a minute later, you be gettin to heisenberg uncertainty level by that point.

Boy, this done gone way beyond topic, want to know about the butterflies in South America?
rob the frustrated not quite physicist

Medium Rare!!! DaggaRon, you're killing me! I am falling out of my chair. I can't type. This is hilarious!

DHA (Rob), you're not making any more of an ass of yourself than a great many others (and its always heartening to see a true believer of science in the forum), but its a bit more complicated. First of all, that business about equal and opposite reactions applies to forces, not energy. Worse yet, Newton's force equivalence is an integral expression, not an algebraic one (as many have incorrectly tried to make it for momentum calculations). He recognized the integrated differential time element in the relationship. You acknowledged that in your pushing analogy. Remove the integration of the problem and you also damage the analysis. This is one problem with the ballistic pendulum and assumptions made about "residual energy" therefrom.

So, that makes it more than a trivial calculation and its why I told Overkill that a softpoint will always hit harder than a solid. It also means that the impact of the bullet and the recoil, while loosely related, are not always equal and in fact don't need to be. As it generally happens the bullet accelerates over a distance of 18 to 26 inches in a milisecond or so and it comes to rest over a distance of (oh, I dunno) 6 to 60 inches in a milisecond or three depending on how things turn out, how its made, what it hits, and so forth. So they are similar, but that is largely happenstance.

Saeed and DaggaRon (and you) are of course right that any large animal is not going to stop moving because of the force of the impact. That's why I proposed the swing test. I wish once and for all time we could have this demonstrated (on video) to the satisfaction of all parties to the question.

Maybe we can put a meat thermometer inside for DaggaRon! I like the idea of a new crank index based on thermal units. How about Optimal Game Cooking Weight? Maybe we should use the existing steak doneness scale? Of course, for dangerous game we should be conservative and insist on calibers which produce "well done", no marginal medium-rare medium bores, what?

I am not fond of converting hunter�s forums into lectures in physics, but:
With the ballistic pendulum you are measuring the angle alpha of the deflection after impact and the position of the bullets entry. You must know the M = mass of the �box�, g = gravitational constant, s = distance center of gravity of the pendulum to pendulum axis, Q = inertia moment of the pendulum, m = bullets mass, a = distance of point of impact to pendulum axis. May be that Ackley uses some simplifying approximations.
If you are shooting into sliding boxes a lot of additional parameters have to be accounted for, but you never can get more information out of these experiments than velocity. And for this question we have better techniques today.


BTW, a human being needs about 7500 kJ a day, that is roughly 1000 shots KE of a .458 Lott.
Instead of killing power can we ask for a healthy power of our bullets?

Harald,
Thanks for the comments. It is good to have a real scientist patroling the forum, to keep the discourse on the right track. Day to day my work is more rote human service art than science and I only have vague memories of Newton's laws lying fallow in my qourd.

Do you think Ackley used his homemade chronograph to get his wild velocity numbers? This still doesn't explain how he got all that powder into those cartridges!

And you do concur that the seemingly vanishing kinetic energy of the bullet is warming up the critter a fraction of a degree, right?

Well done for dangerous game and medium rare for plains game is a great idea.

Norbert,
Thanks. That is just what I was looking for. However, now I must get a definition of the "inertia moment" of the pendulum. Ackley's pendulums were typically 90 pounds when absorbing 100 grain 6mm bullets. Overkill will probably need moose size pendulums, so it would be helpful to be able to calculate the proper inertia moment values. I am serious. I will have to go crack a book if I can't get the info here. For educational purposes please. Sum buddy who know?

Never mind.

[ 07-23-2002, 03:59: Message edited by: The Cool Guy ]

Norbert,
Ain't the internet great. Physics on the video screen with a search for "moment of inertia":

http://www.physics.uoguelph.ca/tutorials/torque/Q.torque.inertia.html

for something really simple and more than 50,000 more links to homework assignments, so I can fully understand this concept I had in physics more than 25 years ago. I should've been a physicist.

Harald..!

I think that the best "stopping power" test will be to put sand into a 200 l barrel and put it up on a table. And then shoot it and see if it move. 200 l of sand will have a weight of around 300 kg. It is like a big moose then...!

I can do this test if I want. I have some 200 l barrels...!

What do you think.. would it prove anything