Author Topic: Taylor Knockdown Formula (Read 3141 times)

358jdj · « **on:** February 14, 2007, 08:13:13 AM »

The Taylor Knockdown Formula is a common way of calculating the hunting capability of various firearms and loads. Does anyone know of a site which lists recommended knockdown values to various types of game and ranges?

I hope someone knows where to find this information.

Good hunting to you.

Graybeard · « **Reply #1 on:** February 14, 2007, 08:18:41 AM »

Taylor developed the forumla specifically for use with solids in big bore RIFLES on dangerous game. It has since been perverted by many to do a lot of things it was never intended to do and for which it is really NOT applicable. What you are looking for is one of them.

358jdj · « **Reply #2 on:** February 14, 2007, 08:48:43 AM »

I follow you Graybeard. I guess my real question is I am shooting a 30/40 Krag in a 14' Contender. Loaded with 173 Flatpoint, Gascheck, Cast bullets at about 1,500 fps, how big of game can I expect to cleanly kill? The Taylor Index number for the load is 11.

Thanks for the great website and help.

jhalcott · « **Reply #3 on:** February 14, 2007, 09:22:11 AM »

You SHOULD increase velocity to as near 2000 fps as possible. You didn't say what alloy you use. A 15 bhn(Lyman #2) Will take game a little larger than EASTERN white tail deer.I used a load similar to yours on "problem" deer on a golf course. Although none got away,there were a few deer that ran about 100 yards or more. The faster load stopped them much quicker.

Graybeard · « **Reply #4 on:** February 14, 2007, 10:20:37 AM »

The Taylor formula has ZERO application to your load. Matters not if it's 11 or 111 it tells you nothing about your load. I would agree the velocity is a bit low for it but increasing it isn't going to change a whole lot other than trajectory. Still using Lyman #2 you should get some expansion and the more velocity you crank out the more expansion and at longer ranges.

As to what game the load is suitable for it's fine for deer/hogs/etc. If you want to go to larger/heavier game I'd up the bullet weight to 200 grains personally and still try to get the velocity up to 1800 or more.

WL44 · « **Reply #5 on:** February 14, 2007, 10:19:42 PM »

358,

GB is right.

As I understood it Taylor was based on the ability of a big bore rifle to "knock out" an elephant with a head shot which missed the brain (hence the name "Taylor Knock Down Values"). The idea was to provide a comparable value for various chamberings. The idea, as I recall, derived from wanting to walk among the herd and drop as many as you could and then walk around and administer the coup de grace afterwards, whilst those that you hit less than perfectly were still out cold. Such was the world of the ivory hunters / poachers of yore!

I have seen a website that has some or other numbers somewhere, but I too think it's an exercise to do, but one where you must allow for the shortcomings.

Taylor KDI was based on non-expanding solids, as I recall, so as soon as you have velocity and an expanding bullet things will likely go horribly awry in the values.

I think its useful to compare hard cast flat nosed revolver loads for example - to get RELATIVE values. But then I like to "play around" with this kind of thing.

There are various other formuale out there that have tried to address Taylor's "shortcomings" (read application outside of the intended use) if you look around.

Lone Star · « **Reply #6 on:** February 15, 2007, 04:12:02 AM »

To expand a bit more....Taylor himself stated that for quantifying the "killing power" of a cartridge on thin skinned game, he believed that the use of kinetic energy values was as good as anything else.

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Lloyd Smale · « **Reply #7 on:** February 15, 2007, 08:25:18 AM »

no animal gets knocked down or knocked out by any bullet I dont believe in either of the methods of measuring gun power. What kills an animal is hermorging and what knocks down an animal is interupting its nervous system. Theres nothing mistical about it. Having a gun with enough energy to push a bullet into the boileroom of an animal kills it plain and simple. Put a hole in an animals heart or lungs and its dead whether its a 22 caliber hole or a 50 caliber hole. Only advantage to a bigger caliber is a bigger hole and quicker bleading. Thats why handguns shooting cast bullets with relitively low levels or engery kill as well as a rifle with twice the energy rating. They penetrate every time into the vitals and when they do they keep right on going through the vitals and with there long wound channels disrupt as much tissue as a high velocity gun that mushrooms and creates a wider but shorter wound channel. Thats why a properly hit deer with a bow will only go 30 yards or so. The 3 blades on the broadhead have opened up lots of blood vessels. Every preaches the high velocity fast expanding bullets as the quickest way to kill but there have been studies that prove that with tramatic wounds like the ones they cause the body has a tendency to go into shock and shut down blood to the wounded area. Good example is a soldier that gets his leg blown off and doesnt blead to death but cut the main artery in your leg and see how long it takes to bleed to death. I guess im getting a little off topic here but im bored!

Lone Star · « **Reply #8 on:** February 15, 2007, 11:15:50 AM »

Lloyd I'm 100% behind you on "knockdown". No shoulder-fired bullet has enough momentum to knock a game animal off its feet, let alone throw it through the air as I have often read about on these pages. All any thinking person has to do is to shoot at a 100# stack of bound newspapers with his .300 magnum rifle. It doesn't go flying off the table, it just sits there. The Mythbusters TV show tried this with a pig carcass suspended from a line. They shot the carcass with handguns and rifles up to an '06 and the carsass didn't move at all. It only moved when they fired a .50BMG at it point blank - then it swung around a little. The movies have made even intelligent thinkers into idots by perpetrating the myth that a shotgun slug can somehow throw a person through a plate glass window....

.

MS Hitman · « **Reply #9 on:** February 15, 2007, 04:53:54 PM »

Oh come on guys; haven't you heard of "energy dump"?

No point in wasting all the energy by shooting through an animal.

Graybeard · « **Reply #10 on:** February 15, 2007, 06:08:36 PM »

Yup, heard of it and been in my share of er ah Discussions of it here at these forums. I figure my opinion of it is about the same as yours and that of most anyone who's actually been out there hunting with handguns any period of time.

WL44 · « **Reply #11 on:** February 15, 2007, 07:23:37 PM »

I agree with pretty much all of that - but wanted to give a bit more insight into Taylors Index and what he based it on (as I understand it).

The "knock down" in that case came from - for lack of a better description - some sort of concussion effect apparently possible with shots on elephant close to the brain. I've no personal experience of it, I'm not trying to sell the concept and I was rather trying to explain why Taylor's numbers probably DON'T do much for most of us in our hunting circumstances.

Do I sometimes play with (various) of these formulae? Sure. Is it useful? I'm not sure, but aside from personal experience all of these have some kind of relative value if you know the limitations and allowing for the limitations means you are guessing anyway!

Lloyd / Lonestar I agree - Its as simple as saying that a rifle that doesn't bowl you over when you fire it is not sending any projectile with enough energy to do that when it impacts. I've also seen some dramatic video footage (don't try this at home type stuff) where a guy donned a bulletproof vest with a ceramic plate and was shot in the chest a couple of times whilst standing on one leg (yes he looked sober!). He wasn't knocked down either.

redhawk500 · « **Reply #12 on:** February 25, 2007, 12:02:22 PM »

Taylor's reference standard was the .375 H&H with a knockout value of 40. An interesting asside is the value of the .500 Linebaugh, 435 grain at 1300 fps, makes 41! Solid to solid, a bigbore handgun is awesome.

Lloyd Smale · « **Reply #13 on:** February 25, 2007, 01:50:45 PM »

and thats an example of how flawed it is. You know im personaly a big fan of big bore handguns and know there capabilitys but if faced with a charging buffalo or lion id sure take a 375 h&h any day of the week over any handgun!!!! Id hunt the with either but for a stopping gun id take the rifle anyday.

Quote from: redhawk500 on February 25, 2007, 12:02:22 PM

Taylor's reference standard was the .375 H&H with a knockout value of 40. An interesting asside is the value of the .500 Linebaugh, 435 grain at 1300 fps, makes 41! Solid to solid, a bigbore handgun is awesome.

Greybeard · « **Reply #14 on:** February 25, 2007, 05:03:32 PM »

All it actually shows is what I've been trying to get across all along. The Taylor formula has no application to handguns. It is what it is yet folks the world over just keep on trying to apply it to things it was never meant to apply to. You can bastardize it all you want but the numbers you come up with when doing it are as meaningless as ft. lbs. of energy and folks just keep on thinking that one has meaning to. NEITHER DOES.

MePlat · « **Reply #15 on:** February 26, 2007, 02:11:10 AM »

I've never read by anyone who has used a 375 H&H on Cape Buffalo refer to it as a stopping rifle.
Anyway I agree to the Greybeard idea to an extent but there has to be a way to relate or to put in perspective the power of different handgun cartridges. The problem that we have is we have all this negativity concerning The Taylor KNOCKOUT (not knockdown read the book) Values and energy figures but we have none of the the same people offer anything any better. They just say it is useless. If something is useless then there must must be something that useful so what is it.
Please think of something useful to educate others like myself so we all can't be wrong.

Lloyd Smale · « **Reply #16 on:** February 26, 2007, 09:51:39 AM »

are you saying that a 375 has never been used to stop a charging buffalo? I think theres been a few stopped by smaller guns then that. I dont remember saying that it was a stopping gun or used for such. Just that if i were faced by one i think id be in better shape then with any handgun. I personaly dont see why people get all in a bunch about having to rate the power of a round anyway. If you use and hunt with a big bore gun your probably experienced with it enough that you know what its capable of. Is there really anyone out there that doesnt know that the 500 smith has more power then a .357 or even a 454? Why do you have to put a number on something thats common sense. The taylor knockout figures were suppose to relate to how much bullet and velocity it took to knock say an elephant out cold. Something that I really have doubts to as if any gun is really capabable of doing reliable. Taylor knock out and the old ft lbs of energy figures are good for sitting around the campfire and bragging about my gun is bigger then yours but neither add up to much real world use. Id say if anything the best meaurement of a guns abiltiy to be used on different sized animals it would be penetration Put a hole though an animals heart and its dead simple as that. If you have combination of enough bullet weight and velocity to put that bullet into the heart or brain from any angle you will need to in the field you have enough gun. Im as guilty as the next guy and still find myself quote ko power and ft lbs of energy to get my point accross but i really dont believe anyone has come up with an accurate way of comparing everything from a handgun to a high velocity rifle to a big bore rifle other then the experiences of the people who use them.. .quote author=MePlat link=topic=111763.msg1098351769#msg1098351769 date=1172495470]
I've never read by anyone who has used a 375 H&H on Cape Buffalo refer to it as a stopping rifle.
Anyway I agree to the Greybeard idea to an extent but there has to be a way to relate or to put in perspective the power of different handgun cartridges. The problem that we have is we have all this negativity concerning The Taylor KNOCKOUT (not knockdown read the book) Values and energy figures but we have none of the the same people offer anything any better. They just say it is useless. If something is useless then there must must be something that useful so what is it.
Please think of something useful to educate others like myself so we all can't be wrong.
[/quote]

MS Hitman · « **Reply #17 on:** February 26, 2007, 04:22:48 PM »

I believe a good bit of the application of TKO numbers to handgun rounds got started by Ross Seyfried and was later taken up by John Taffin. Go back and read the series of articles by Ross in the early to mid 80's and you will see what I mean.

There is a big difference between stopping and killing, especially when applied to dangerous game. In most areas, the .375 H&H is considered the minimum caliber for buffalo. Most stopping guns I am aware of start with a "5" or "6" in their caliber. Depending on the situation, a .458 Win Mag may not be "big" enough to give one comfort. Smaller calibers have been used to kill buff. Elgin Gates killed one with a .357 Mag; after it ran him up a thorn tree. I saw the footage of Larry Roger's shot on a Cape Buff with his .416 Taylor in an Encore handgun. I was a little over a quater-mile from him when he took the shot; I heard the bullet impact. I doubt the buff would have been able to tell any difference had a rifle in the same caliber been used.

I am certainly not a fan of kinetic energy, as it favors velocity over bullet weight. Revving up the velocity on light bullets can give fantastic energy levels, but very poor performance on game animals. High energy figures do little when an animal runs away with a very nasty surface wound because the bullet failed to penetrate properly. Is there some indexing number or formula that may be used to rate one handgun cartridge with another? I do not have the answer to that one. I do however agree with Lloyd, a modicum of common sense will go a long way to successfully matching caliber and bullet with the intended game.

Graybeard · « **Reply #18 on:** February 26, 2007, 05:43:35 PM »

Yup guys but the biggest problem as I see it on forums such as this with folks who want a neat package or number to compare is that they have precious little real world experience to base a common sense decision on. So they look for a magic number that tells the story that only experience will tell them. Those that have gotten out and used the handguns on game for years have a pretty good basis for making decisions but there is just no neat magic number any of us can give folks looking for it and thus they fall prey to the ft. lbs. of energy or TKO numbers and just assume them to be the do all end of answer.

Folks as I've been saying for many years and now even the major name magazine writers are finally actually admitting they really aren't what they've been telling you they were all these years.

MePlat · « **Reply #19 on:** February 27, 2007, 07:13:38 AM »

OK, as I said above I a mostly agree with Graybeard on this subject which is inline with you Lloyd so keep your shirt on ok.

If there is no way to quantify power on a handgun is there a way to quantify power in a rifle?

Is there a way to quantify power (that eventhough none is accurate measurement to the ninth degree) is better than the others in handguns and /or rifles?

We have Energy figures, Taylor KNOCKOUT values, momentum, Veral Smith's dispalcement velocity formula, crystal ball technology, Old Wives Tales, etc.. Of those mentioned is there one that either Graybeard or Lloyd Smale would pick as being more accurate than the others?

Are we walking in the dark with no light to show the way?

Beers · « **Reply #20 on:** February 27, 2007, 07:34:43 AM »

They already mentioned the best formula: common sense. If you've got to quantify things, go hunting. Count what you come home with.

Lloyd Smale · « **Reply #21 on:** February 27, 2007, 07:57:43 AM »

meplat i guess in some way they all could be used if you really need a way to rate a gun. But i guess i just dont see a need. I surely dont want to imply that i know it all as i sure dont!!! I guess i have my own opinion on what works in a gun and use that. If someone wants to use one of the other ways to rate a round, go for it. Just dont believe that any of it is written in stone and that you wont get a believer in one of the others agruing with you.

Quote from: MePlat on February 27, 2007, 07:13:38 AM

OK, as I said above I a mostly agree with Graybeard on this subject which is inline with you Lloyd so keep your shirt on ok.

If there is no way to quantify power on a handgun is there a way to quantify power in a rifle?

Is there a way to quantify power (that eventhough none is accurate measurement to the ninth degree) is better than the others in handguns and /or rifles?

We have Energy figures, Taylor KNOCKOUT values, momentum, Veral Smith's dispalcement velocity formula, crystal ball technology, Old Wives Tales, etc.. Of those mentioned is there one that either Graybeard or Lloyd Smale would pick as being more accurate than the others?

Are we walking in the dark with no light to show the way?

Graybeard · « **Reply #22 on:** February 27, 2007, 11:51:55 AM »

Quote

Are we walking in the dark with no light to show the way?

Well no we have experience to show the way. But as far as any one formula or magic number to do it sadly no there is no such. If there were then they would all agree but they don't not by a long shot. There are many different notions of how to assign a number to use in comparison but if you use all them and then look at how they rank different rounds you'll see wide disparities. That to me is enough to say none have a lot of merit, altho I guess all have some limited merit. But everyone of them will at times rule out a really fine round for the job and all will at times tell you something is fine that really isn't.

Listen to those who've done it and see what has worked well for others and rest assured it will work well for you as well IF you place the bullet in the right place.

MS Hitman · « **Reply #23 on:** February 27, 2007, 05:42:25 PM »

I have found the less experience one has, the more he/she tends to rely on "absolutes". While I have no problem going after big and/or dangerous game with a handgun; I do so with the knowledge and experience that the handgun, no matter how large, is not a large rifle. Does this mean I can not cleanly, humanely, or effectively take the game I am after? Absolutely not! Rather than try and apply a number to a particular cartridge; I'm going to apply some common sense to my cartridge selection.

Common sense will light the path through the plains of ignorance; we just have to use it.

Lone Star · « **Reply #24 on:** March 01, 2007, 05:00:42 PM »

Quote

...I'm going to apply some common sense to my cartridge selection....

Common sense is a rare commodity in today's society. To expect it from others is to crave disappointment.

.

MePlat · « **Reply #25 on:** March 03, 2007, 02:45:34 AM »

Lets revisit our discussion of Taylor knockout values. If one goes to the linebaugh site John Linebaugh say in it we have the most perfect way to rate a cartridge "The "industry" give us foot-pounds of energy figures to ponder over on cold evenings. We could shoot phonograph needles at the speed of light for, say, "20 tons" of energy and never stop anything bigger than a bull pack rat. Or we can shoot heavy .44 and .45 caliber slugs and do things very few would believe. I long ago quit using the foot-pounds formula ( using it only now to figure pressures ) and went to the " most perfect formula" by the late John "PONDORA" Taylor of African fame. Taylor’s formula that he called "Knock Out" is figured this way:"
Also the pornmaster of gundom Gary Reeder uses Taylor knockout to rate cartridges and energy, Randy Garrett uses Energy figures and Taylor Knockout to rate his loads, I've read John Taffin on his using Taylor Knockout to rate cartridges, Ross Seyfried has too.
Do these guys lie to us or are they just not intellegent? What are their motives behind using Taylor Knockout Values? Is it to fool the masses to use their cartridges or what. If they lie about that what else do they lie about? Should we be cautious of even these esteemed men?
See that is where the questions come from when one tries to make one look inexperienced or dumb when one mentions Taylor Knockout Values, energy, momentum, etc..
See the problem with trying to make some insignificant somebody look dumb it kinda makes Reeder, Linebaugh, Taffin, Seyfried, and alot of others look dumb too.
I just know that none of you were trying to make these fine men look like they were lacking in intellegence.

Lloyd Smale · « **Reply #26 on:** March 03, 2007, 04:26:45 AM »

I for one wasnt trying to make anyone look dumb! I was just giving my opinion and it is that none of the ways we rate handguns or even rifles for that matter doesnt have flaws. As far as making linebaugh and taffin and others look dumb thats about rediculous. They have more experience and knowlege then proably everyone combined on all the internet fourms. But just because they have there believes doesnt mean that i cant have mine as long as there based on my experiences and not someone elses. I know John personaly and we even share a best freind that is another man that probably knows more about handguns and what works then anyone else in the country. Why because hes probably killed as much game as anyone (at least that i know) with a handgun. If you HAVE to rate a handgun theres probably not any better way then with Taylors theroy but im not a writer or a gun builder that needs to rate them. If you feel you have to defend John Linebaughs thoughts or John Taffins thoughts to me youve got the wrong man! Theyve both been big influences in my life and we all could stand to be more like them. If you look at Johns words he says we have the most perfect way. Not a perfect way. Im not going to get in a pissing match with you because i have my beliefs. I post what i believe and you can either read it for what its worth (probably not much) or post your beliefs so someone can get another side to look at. Nobody has all the answers and if we did we surely wouldnt be here.

fowler · « **Reply #27 on:** March 03, 2007, 05:02:24 AM »

I think at the end of the day people simply must have some quanifiable formulas to understand relative capabilities of our weapons. This gives us confidence in what we have to hunt with, an some understanding of its limits. Lets face it, any handgun is far inferior to a good rifle for hunting big game but can still be very effective in their own right. TKO is simply the only one formula developed that relates to handguns reasonably. Is it right or does it always make sence? No! if I remember correctly a 250gr 44mag bullet at 1400fps has about the same TKO level of a 335gr colt bullet at 950fps. Are these two going to perform on game the same? No. It also does not account for bullet design, certainly if the 44 mag was a hollow point and the 335 was a LFN bullet we would see world different terminal performance. But in the end it is still the easiest to understand formula for handguns. I know some who look at the IPSC powerfactor as power levels too, but those have little bearing on hunting performance but is more information to work with.

When it is all said and done time in the feild is the best formula its just not very good and giving info on the net with. Bullet placement, reasonable distances, good bullets, will always be more important to cleanly killing game than any formula will ever show.

Gather all the info you can, get the best equipment you can afford, make your self confident in your equipment, practice like hell, get closer and lets all enjoy this wonderful sport of shooting and handgun unting.

Graybeard · « **Reply #28 on:** March 03, 2007, 07:32:37 AM »

Actually the TKO isn't the ONLY one that can be applied to handguns and it's really no better at predicting the real world effect than is momentum and there are others that don't put so much weight on velocity as does ft. lbs. of energy. None of them are perfect and none of them always lie.

As to the writers you mentioned they kinda sorta MUST put forth some simple easy to understand number so the uneducated and inexperienced masses can relate to what they write. I'm sure editors require it of them. Do I believe any of them really believe it's the do all end all of predicting how a bullet will react on game? Nope I sure don't. It's just a convenient number they can toss out that is easy to compare to something else and while it's no better it's also no worse than any of several others.

But regardless of who uses it that does NOT alter the fact it is NOT what Taylor designed it for and he NEVER EVER put any study into the application to handguns.

MS Hitman · « **Reply #29 on:** March 03, 2007, 10:55:57 AM »

My prior observation is merely that; an observation. Whether or not it applies to an individual or group on this or any other forum is inconsequential to me.

For the purposes of calrification, I will offer the following quotes from African Rifles and Cartridges. ENERGY. Surely the most misleading thing in the world- where rifles are concerned. Gunsmiths invariably quote it because, particularly since the advent of the Magnum, it is decidedly flattering to the weapons. Personally, however, I take little notice of these figures. They're quite useless if you are trying to compare any two rifles from the point of view of the actual punch inflicted by the bullet.... pages 11-12 Further into page 12, he begins to develop the use of the TKO for the reader, making the following statement "... suffice it to say that the final figures agree in an altogether remarkable way with the actual performance of rifles under practical hunting conditions." At this point, we can follow the application of theory to practical field experience.

Realize, as does Taylor, that no mathematical formula is perfect. On page 124, he discusses the .375 H&H by starting his discussion with the following, Undoubtedly one of the deadliest weapons in existence. Halfway down the page, he makes the following remark, Altho my formula gives this rifle a Knock-Out value of 40 points, I must regretfully admit that does not really do full justice to it.

Kinetic energy is biased toward velocity as the value is squared. The TKO is biased toward heavy. large caliber bulets as both these figures are in the numerator of the formula. The energy value is purely a mathematical expression and has no bearing on field experience, while the TKO was developed from experience in the field with heavy rifles used on dangerous game. Study the variables that go into a formula and one will quickly be able to determine how the formulae are biased.

Taylor believed in using handguns and devoted a chapter of this book to them, but as Greybeard stated, did not apply the TKO formula to handgun cartridges.

I strongly suggest one obtain his/her personal copy of the book and read it completely. As with most any other resource, context may be skewed without the full text.

Playing with the formulae is fine, but there comes a time when the realization must be made that these are nothing more than mathematical exercises and merely an attempt to model real-world events. This occurs not only in the gun shooting circles. I constantly run into this from the inexperienced in the surveying and engineering professions. These people take a computer's out-put as gospel and any explanation as to the limitations of the results or their development has no effect on them.