If you can find some articles about the Taylor Knock Out value formula and how it came about, you will find exactly what your looking for in terms of Knock down power.
Unfortunately, I do not remember where I have my articles stashed [img]/ubbthreads/images/graemlins/mad.gif[/img]!!
Anyway, The TKO formula was made up to compare mainly the big bore african hammers for use on heavy game. It was also designed to be used to compare solids where were and still are the recommended bullet for heavy dangerous game in africa.
Because they were dealing with solids, the huge amount of variables we are trying to deal with concerning expanding bullets do not have to be taken into account.
This is perhaps the most realistic formula I have found to determine or compare one rounds effectiveness on game to another. Remember though that this is designed for solids and is not reliable with expanding bullets.
I think this is such a good formula mainly because it giev the three major componants to bullet performance a fair shake. You simply take "Bullet weight X Velocity X Bullet diameter"
If we look at the Kenetic energy formula, velocity is Squared so the faster the round the better it looks using this formula. This is why a 22-250 will produce the same Ft/lbs of energy as a 45-70 when we all know which is better for use on heavy game. Energy is to velocity biased to be really useful over a wide selection of cartridges.
The Hatcher Relative Stopping Power Formula is a good one, complicated but squares the Bullet Diameter value so that it is biased toward the big bores.
If we want to compare a theoretical bullets performance, the TKO formula is in my opinion the best out there because it keeps everything on a more even playing field for all rounds. No velocity bias, no bullet weight bias and no diameter bias.
Only thing is this is only useful until the bullet lands on target and takes on its final form after expansion.
The expanding bullet is the problem here, some work well, some do not, some are consistant, some are not and varying conditions in the field can take a normally great performing bullet and cause it to perform differently then normal.
Point is, put the bullet on the mark and this is all a moot topic. A bullet punching both lungs of a big game animal will result in a dead animal 100% of the time, as long as the bullet will penetrate deeply enough to get both lungs.
ps- I will say kenetic energy does have its place and that is in the varmint rounds. Violent bullet expansion is a result of kenetic energy and a lightly constructed bullet. Here you can use energy to compare different rounds with good results. Thats why a 223 and a 22-250 shooting a 50 gr V-Max will perform so differently at 300 yards. Its all energy to rip that bullet apart, at the same time doing the same to the vermin [img]/ubbthreads/images/graemlins/grin.gif[/img]!!
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
[ QUOTE ]
He says that if a bullet actually had enough power to stop or knockover a animal the gun would do the same thing to the person shooting it.
[/ QUOTE ]
This is the sentence to which I was responding. I hope my responses were helpful in this context. Your explanations of knockdown power are getting harder and harder for me to nail down so I will stop here. If Kirby is in tune with what you mean then you are in good hands.
The shock factor I think you are talking about was illustrated to me on that bear I recently shot. I shot all the way through the bear and the exit hole was not very big. The bullet did not hit solid shoulder or back bone but the bear fell over. He did get back up and then die quickly. The part that amazed me is that he fell with the shot. Is this the elusive "knock down power" you seek? Dunno?
Another good read on a related topic is the book: "Handgun Stopping Power" By Evan Marshal and Ed Sannow. They did a comprehensive study on which handgun loads resulted in a "one shot stop" compared to other rounds. It is a fairly tight definition regarding what they consider a one shot stop and they do a good job comparing apples with apples.
In the book they cover the hydrostatic shock (main contributor to knockdown?)that occurs as well as temporary wound channel (the part that explodes varmints) and permanent wound channel concepts. These are the elements that set bullets appart from arrows. Your police friend may even have access to this book through the department library or you might be able to find it in the regular library.
I will continue to look in on this post. I find this sort of subject to be quite interesting.
GRAVITY. It's not just a good idea. It's the LAW!
The idea of knockdown or shock value lies much more with were the blow is delivered. A boxer hit in the midsection may stay on his feet, the same force blow to his head may knock him down. To my way of thinking a strictly shock injury incapacitates its victim until the nervous system recovers. Trauma is what causes an animal to die.
A high shoulder hit as GG shoots for causes a shock that is transfered into the nervous system through the smashing and disruption of tissue near the spinal cord. The trauma this wound channel creates (blood loss, vaccum seal loss of lung cavity) is what causes the critter to die. Depending on the shock value or force that is delivered to the nervous system, dictates weather the animal will regain its footing before the trauma kills it.
Many animals are shocked to the ground and die before the nervous system recovers. Just as many are shocked to the ground, recover, run, and collapse from the blood loss.
A coworker some years ago was shot in the head with a 25cal pistol. The bullet glanced off his skull, but knocked him to the ground. (for 2 days) He suffered very little bloodloss and made a full recovery. Did that bullet knock him over? No. The shock it caused to his nervous system caused him to calapse.
If he was shot with a red rider BB gun in the head he probably would have stood there and got mad.
So lerch, it seems to me stopping power or knockdown power is real, depending on the location of the hit, and that which is hitting is large enough to inflict nervous system damage.
If this reasoning still has the deputy in disbelief it's time for a demonstration.
Put the deputy in his own cuffs.
Hit him on the head with your brass drift hammer.
Hit him on the head with a 5lb mall.
He'll catch on. [img]/ubbthreads/images/graemlins/wink.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]
These terms mean different things to different people.
Hollywood can slam a man against a wall ten feet away, and a lot of people have seen it happen. Now, if it happens to be a double barreled load of buckshot, at close range, it might cause a body to be forced backwards? Seems reasonable, to me?
Knockdown power, as a concept, is a little harder to understand. I prefer the term, "BANG/FLOP". I don't think it means "Bang, your dead" but it does tend to knock their feet from under them.
An interesting question that I have posed several times is: does your animal fall toward you, or away from you, most of the time? I know that I have seen a few animals fall over backwards, at a facing shot, but it seems to me that they are just as likely to fall with their feet pointing toward the direction of the shot as they are to fall over the other way. This presupposes that they are dead when they hit the ground, no thrashing about. Occasionally, they roll over with the feet pointing straight in the air.
If discussing African game, foot pounds is the only yardstick I know of that makes sense, but tossing in bullet type, that gets real complicated, solids and soft points, etc. Lion loads and Cape buffalo loads are completely different, even if the numbers are the same.
Nothing wrong with "starting another argument". Defending an opinion can be enlightening.
Sorry Lerch. I have been doing load development/tinkering for a kagillion rifles this week and haven't had time to get into this one.
I read what Kirby said and he almost responded verbatim to what I was going to say. 4kie, jb, and others had very good points as well in relation to Newtons laws of physics. When a bullet is fired from a rifle, it imparts the exact same force rearward as it does in momentum moving forward. The kicker is that you don't feel it because the weight of the rifle helps absorb the energy and there is some lost in kinetic energy or heat transfer if I remember correctly.
The TKO or whatever it is called is also another great point that Kirby brought up. I have looked at that explanation a lot over the last several years and have found it to be very useful. I think ammo manfucturers should list this method along with their ft/lb method in their brochures.
Also, I agree with 4ked horn that blood loss in conjunction with tissue damage and nevous system disruption combine to kill the critter.
In my experience, hydrostatic shock from the bullet forcing liquids out in rapid expulsion to the outreaches of veins and capillaries is also a very deadly force. Ever shot a deer in the neck and had it's bloodshot eyes pop out of their sockets with rivers of blood coming out the corners of the tear duct? Gory I know, but that is hydrostatic shock described in nasty detail. [img]/ubbthreads/images/graemlins/blush.gif[/img]
Kinetic energy is a component measure of heat transfer. That is why Vietnam vets that were shot in the leg complained of a horrific burning sensation as the bullet passed through. It also explains why bullets seem to "melt" through weak or soft gongs. This is also very deadly in it's own right.
As for ft/lbs knocking an amimal off it's feet (backwards) I would say that only happens in movies. It would take considerable more mass (like a semi-truck doing 70 mph into Bambi) for the animal to get "launched".
So your question about "knockdown" power can be answered in one sentence. Yes it exists in some form that must be determined with one's own terminology, but it is not the only thing that kills.
Hope this helps. [img]/ubbthreads/images/graemlins/wink.gif[/img]
My research and experience points to the theory that wound channel or shock (knockdown power) will take a game animal though in different ways.
OK you do the classic broadside, front leg foreward double lung shot.
On impact the animal may react quickly, may fall down but will almost always get up and travel 30-100 yds, as lungs fill with blood and the game animal bleeds out internaly or perhaps externaly depending on where and how big the wound channel is.
Now you move the crosshairs to the place of most resistance on a animal, the scapula (shoulder blade) hit him here with a light for caliber fast bullet.
The bullet impacts the scapula and tranfers all its energy to the center of the shoulder, lots of things happen, A massive shock wave, sends the blood backwards through major blood vessels, it also travels the length of the central nervous system to the brainstem. DRT,DRN, game has been found to have ruptured blood vessels in the brain even though it was shot on the shoulder. Bullets definately have knockdown power, it just has to be placed in a high resistance area to be utilized. The larger the game animal the more heavily constructed a bullet can be and still utilize hydrostatic shock.
Am I making sense here?
[ QUOTE ]
The bullet impacts the scapula and tranfers all its energy to the center of the shoulder, lots of things happen, A massive shock wave, sends the blood backwards through major blood vessels, it also travels the length of the central nervous system to the brainstem. DRT,DRN, game has been found to have ruptured blood vessels in the brain even though it was shot on the shoulder.
[/ QUOTE ]
Can you tell me where you got this info? Some literature w/some studies done on this could really help us prove our point.