Reloader, education has not helped you , watch a few hunting videos, animals fall down, plain and simple

You guys just cant handle being wrong!

Your insecurities are showing.

If you guys were our nations weapon designers, we'd all be dead.

I guess if we shot a VW Bug w/ a Cannon Ball it wouldn't even budge. HA HA HA HA

Your Ignorance is killing me.

GROW UP!

Reloader

So Reloader, what caliber is needed to knock an Elephant off his feet

Don't believe they make one.

Pound for Pound force for force it would have to be pretty dang big. Espeacially if you were to use the ratios we used in the small deer/Big magnum example.

If you had a bullet big enough and it had enough velocity, we could dang sure give it a try. We'd probably have a hell of a time getting a bullet that wouldn't exit. Plus, that thing would have to be mounted on a tank. HA HA

Reloader

And that specific formula for small deer and big magnum would be?????????

ok, how about this:

a 180 gr bullet (.00166 kg)
at 3000 fps (914 m/s)

has a momentum (mass times velocity) of about 1.52 kg-m/sec

a 3 lb brick (1.36kg)
thrown at about 3.6 fps (1.1 m/s)

would have about the same momentum

would a 3 lb brick thrown at a 150 lb deer (or 150 lb man) at 3.6 fps (about 2.4 mph) knock him over?

olarmy,


Read back up on your equations and look at energy transfer.

The assumptions everyone is making would suggest that all energy (Like 4063 ft-lbs fired from a RUM) is completely disolved at impact and there is no effect on the game.

If you believe that, you need to talk to some of your well educated friends.

How about this lets just settle it once and for all:

If I get you guys a 10"x10" Ballistic Plate and you strap it on your chest. Will you let an expert marksman of your choice shoot the plate w/ a 300 RUM w/ 4063 ft-lbs of energy.

W/ the way you all are explaining things the bullet would just hit the plate and fall down.

ANY TAKERS?


Didn't Think SO!

Reloader

as opposed to suggesting that people shoot at people.... Get a saw horse, drape three 50 lb bags of sand on it and shoot one of the bags of sand with your favorite 30/06 or 300 Magnum. It won't fall over...

The ENERGY of the bullet is dissipated in tissue distruction (and a minimal amount of heat). It is the MOMENTUM of the bullet which would tend to push the deer or sawhorse over, and there ain't enough there to do it.

If the bullet had enough momentum to push a deer over, the rifle would have enough momentum to push over the shooter...

olarmy,

When a bullet is in motion at a very high energy level and hits a small deer (sitting still) the energy is transfered to the deer it doesn't just disolve into thin air.

You must be one of those "Penetration" hunters that has never knocked a small deer off its feet. Well, I have seen several knocked off of their feet w/ Big Magnum Rifles and explosive bullets. Until you have experienced it yourself, you have no room to speak.

Their are piles and piles of articles about this debate. Many are written by very well known experts. Even those experts have heated debates on this issue. We are certainly not experts, we just give the results of our experiences in the field.

My results are of small deer being knocked off their feet at close range w/ high velocity explosive rounds. If you have not seen it then, you have no room to talk.

Reloader

ok, I thought we were discussing physics and not the reaction of animials to stimuli. But if you think I have no room to talk, guess the conversation must be over...

I have seen a deer flip upside down and land on its back after I hit in the lungs with a 180 gr from a 30-06. My uncle shot a cow elk a couple years ago with the same rifle and it did pretty much the same thing. It would appear that the animals were literally knocked off their feet in both cases. But we know better because we understand basic physics. There are lots of cases when the animal just stands there and takes the shot with no apparant reaction at all.

If the animal was really "knocked off its feet", it would be from momentum, not energy. And there isnt enough there to do it. You as the shooter are hit with more momentum than the animal will see in even the best circumstance. And if it doesnt knock you over, it wont knock the animal over either. It doesnt matter if the bullet stops quickly as in the steel plate analogy either. Try hanging a steel plate in front of the sandbags on your sawhorses and see what happens. Bet it doesnt fall over. Energy is a different thing. Energy is not momentum or a force. There is much more energy going out of the end of the rifle barrel than there is hitting your shoulder. But the force is the same, and force is what matters when it come to "knocking" things over.

Reloader, what is your degree in? Civil Engineering? Just curious, I am finishing up my degree this term Its been 5 years of school, i am way past ready to be done!

SeanD: it's nice to know that the laws of physics haven't changed since I was in engineering school, 40 years ago! Congratulations on your upcoming graduation!

Thanks

I don't know anything about physics but a 458 Lott all but knocked me into the second tuesday of the following week.

Now that I do believe! And you know there is something strange about gun nuts when you get up from the second tuesday the following week and shoot the thing again

Sorry about causing all this fighting about thoretical matters. That wasn't my intention. The guy I qouted had a realtime experience, with a certain animal and a certain caliber which I found interesting. So I asked the question to see if all the answers could give some direction to what caliber was best suited to a given animal. I mean clean, quick kills are what we're trying to do... right? (In the field, not on this board...)

Told myself I wasn't going to get into this, but couldn't resist!

<opinion on>
I deal with Professional Engineers daily. Heck, I am married to one (Civil). When someone prefers to throw around titles instead of experience, I remember why I have never bothered taking the P.E. exam. Thank goodness I am Electrical, so I have career options without it!

But......both sides are right, sort of.

<opinion off>
<facts only>
Momentum is conserved. 30 seconds of math, using an actual field experience of my own that many would call a 'knock down'.

165 grain Nosler BT, 300WSM, impact estimated at 2800 f.p.s.

165/7000=.02357 lbs
.02357lbs*2800ft/sec=65.999999 ft*lbs/sec
Deer estimated at 100 lbs for convenience.....
65.999999ft*lbs/sec / 100 lbs = .6599999 ft/sec

So my bullet impact caused the deer to accelerate to about .659999 ft/sec

<fact mode off>
<opinion mode on>

That is not fast enough to make any healthy animal fall down. What I saw in my scope was deer in crosshairs, <bang>, reaim to find deer again, there's a white deer belly in the grass.

In the time it took me to re-aim and find the deer, it was down.

The momentum is not enough to 'knock' down a deer, but if the shock of the bullet stuns it and it goes limp it is enough to make him away fall from you. In the time it takes to see it again, it looks like a 'knock down'.

Call it what you will, but it is enough force to control the direction of the fall, but that is about all.

IMHO, of course!!

Reloader.

I saw a video of a guy wearing a bullet proof vest and being shot with a 308 winchester. His point was that although there was over 2000 Foot pounds of energy being delivered it could not knock him down. Plus that it was a very good vest a little thick for normal carry and wear.

Correct answer

Post deleted by ScottS

The last mule deer I shot was facing toward me, looking right at me, standing in brush that mostly covered its vitals. I aimed for the neck, but failed to compensate for the uphill shot. The shot destroyed the jaw and lodged in the back of the skull. The deer was down before I regained focus from recoil.

When I got to it I found that the deer had done a complete 180 and its entire body was facing the oppisite direction. My guess is that the force of the bullet physically turned its head, and not unlike steering a horse, the rest of the body complied with the inital action. That is the best I can do to explain it, it was weird to say the least. Two things are certian though, 1-the bullet entered at the front of the mouth and lodged in the back of the skull, 2-that same bullet certianly had a strong influence on the 180 degree turn around.

Lets assume just for a minite that it actually were possible to knock an animal off its feet. A couple of variables that might be factors in such a phenomena would certianly be,

1-the stability of the target, or lack thereof

2-a sudden and striking impact like that of a hammer as opposed to a penetrating impact

3-the energy (mass times velocity) and composition of the projectile.

The above deer described is the closest thing Ive ever seen to anything being "knocked off its feet". Im not saying I believe the Hollywood stunts and their depiction of gunshot reactions, but I will say this. People definatley underestimate the power of rifles in this magnum crazed era..

I avoided this thread when I first saw it as I personally think the "knock down" power thing is BUNK!
I've seen some spectacular results and seen animals collapse, but anytime someone starts "knocking it off it's feet" it's definately just a story and they can tell it any way they like.
There have been some good explinations of how the knock down phenominon happens. I've shot animals with magnums and not gotten the instant crumple I expected. I've also gotten the instant collapse with smaller calliber, slower moving bullets. If, and I do meen IF, "Knock Down Power" existed, then once the enlightened engineers had the formula we would all be knocking everything off it's feet!
The energy of the bullet is imparted on the target only to the surface area covered by the face of the expanded bullet. The bigger the mushroom the more energy transfered dirrectly. The deep penetrating bullets don't have a large frontal diameter as compared to a shallow one. A bullet that breaks up, looses the front core, ect. is loosing mass and will then loose energy rapidly. If the bullet has all the energy pushing on a small spot the size of the tip of your finger that area will give way easier than if you had placed your whole hand on it at the same energy level. There are a lot of dynamics involved and people have tried to come up with formulas to prove thier ideas. ( Taylor Knokout Formula ring a bell? ) But as with all things engineered, things don't always work the way we expect. Results are studied and new"improvements" are tried. Often we find the improvement works differently but not really more effectively.

This is an interesting subject and has spawned many heated debates. Here on this board it seems we have already reached a point of personal insults.

Sorry to you P.E.'s, but I work in an industrial environment and it's been my experience that ALL engineers should spend at least two years interning before they can complete thier degree. Things don't work in reality the way book smart engineers plan them. It's not because the math is wrong, it's because there are always variables that are not taken into account. The best engineers I've worked with have been tradesmen who returned to school.
Terminal ballistics is much the same animal. There are dynamics involved that don't fit into little boxes. It's hard to calculate something thats not definable. Yes I can agree that on occasion it appears an animal is knocked off it's feet, but more often I'd say it's common to see a collapse, or very little reaction at all, than it is the flip 'em off thier feet showstopper.

Further variable.....

Get your friend and attempt to push him off his feet. What happens? If only by instinct, he shifts balance and-or moves his feet to maintain his standing position.

Tie his feet together and all of a sudden he's easily unbalanced.... possibly with only a finger-type push.
That's what you're doing when arguing for narrowing the base on your saw-horse or claiming that the narrow track on a deer makes it easy to up-end.

Thump an animal with a bullet that does not instantly disrupt its ability to balance and it almost inevitably remains on its feet, if only momentarily. Disrupt its ability to balance and coordinate (CNS) and you have a spectacular "kill" that drops it on the spot.

Real-world case?
I had to put down an old horse of around 15.3 hands. (A bit bigger than the average whitetail??)
At the shot he dropped like a puppet with the strings cut - absolutely instantly - and rolled onto his back with all feet in the air before settling on his side with only residual nervous tremours.

Had I shot him with a big magnum I could have claimed to have "knocked him down" ... Had I done it, or been watching from 300 yards away it would have looked EXACTLY like it..

Reality was that I brained him from front-on with an oh-so-powerful .222Rem.

In other words,,,, seeing what LOOKS like a knock-down EFFECT doesn't PROVE that knock-down is the CAUSE.

Because I work with stock, and sometimes eat them, I've seen a great many shot animals go down just as fast as gravity can make them. In 99% of cases this was the result of a brain shot from a .22 rimfire. You couldn't get them off their feet any faster, but I'm not kidding myself that it was anything to do with massive energy transfer from the projectile.
As a further variable, consider the difference made by a single inch. A well-placed shot gives what looks like a spectacular "knock-down", while a shot with identical energy transfer that doesn't damage CNS leaves the animal standing.

Cheers....... Cooch

aww come on cooch,

knock down power?

what about the "ugh boot" methodology?

as in if it's furry (or feathery) with a steaming hole you could put your foot in it's an ugh boot!?

the whole argument hinges on the ratio of bullet energy at point of impact in relation to size of target.

and as to how impressive it looks, remember, if the diameter temporary wound cavity excedes teh diameter of the target, it will EXPLODE.

put any .300win mag round into a rabbit.
tell me that isnt funny!