John "Pondoro" Taylor gave his formula in Big Game Rifles ('48) for knockdown power:
mass of bullet (in lbs) times Velocity in ft/sec and diameter in meters
Mike LaGrange discusses the various other measures (Hatcher's Relative Stopping Power and Art Alphin's shock power index) in his Ballistics in Perspective.
jim dodd
Posts: 4166 | Location: San Diego, CA USA | Registered: 14 November 2001
The main thing to remember about Taylors system was that he developed it to predict the performance on thick skinned game only (primarily Elephants) and using solids. It was never designed to predict results for todays premium controlled expansion softs on say the larger plainsgame, which is what the majority of visitors to Africa hunt today.
Posts: 5684 | Location: North Wales UK | Registered: 22 May 2002
Tayler's KO values, are somewhat nebulous, some chamberings just seem to work better than his values would indicate, by his own admission! They are, however, far more accurate than useing Feet pounds of energy, as a guide! His KO values were developed for solids only, and do not work with soft points, as a rule.
Posts: 14634 | Location: TEXAS | Registered: 08 June 2000
I understand that one of the salient factors in Taylor's calculations is that he uses the muzzle velocity only as a single multiplier, not squared as it is in calculations of foot-pounds. Thus, an increase in velocity does not give nearly as large an increase in Taylor's number as it does in calculations of muzzle energy of bullets in foot-pounds.
In addition, Taylor uses the diameter of the projectile as a factor, but bullet diameter does not figure at all in calculations of the kinetic energy of projectiles in foot-pounds.
[ 04-24-2003, 18:13: Message edited by: LE270 ]
Posts: 5883 | Location: People's Republic of Maryland | Registered: 11 March 2001
quote:Originally posted by LE270: In addition, Taylor uses the diameter of the projectile as a factor, but bullet diameter does not figure at all in calculations of the kinetic energy of projectiles in foot-pounds.
Correct, however a larger diameter bullet will cause more damage, thus the credit given to the diameter in Taylors calculations.
You could have a projectile that weighs 500 grains that is as big around as a needle ... it would be 5 feet long. You can see how this would not cause such terrible results when fired into an Elephant. It would pass through him and he might not even know he was shot!
Sure, it is a ridiculous and exagerated situation, but you can see my point.
I like Taylors KO values and reckon they're pretty accurate within the restrictions as laid out by Wendell. They're not perfect, but if you bear in mind that he worked them all out without the aid of modern day calculators and computers he did pretty well.
Taylor's KO factor is just momentum (pounds feet per second) weighted by bullet diameter in inches. He used the 7000 to 1 unit correction for grains to the pound, but he omitted the 12 to 1 corection of inches to the foot, for his unitless abstraction.
His is an incomplete parlor game limited in application to brain shooting elephants with FMJ solid bullets of yore. For reckoning the ability to knock out an elephant with a near miss brain shot in the skull of jumbo.
For a slicker game, throw in the 12 with the 7000 and factor in the unitless sectional density. Then multiply by 100 to convert the resulting 1.00 rating of the classic .375 H&H load to 100 (100% of the minimum effective DGR, oh my gosh what a coincidence, ordained from above?), and: Voila!
This will correct for Frisbee shaped and needle like bullets.
This is the Bwana Saeed Index, or BS Index.
It measures "whomp" or payload delivery ability of big bore rifles. It is merely a ballistic scale. It is not rocket science. Neither is the Taylor KO value.
You can find it under the FAQ section of this web site. Tongue in cheek on all these lethality indices, don't ya know?
Posts: 28032 | Location: KY | Registered: 09 December 2001
One thing about Taylors figures, they seem to match actual field results as well as anybody elses, I suspect he juggeled his figures to match his experience, something a calculator, computer or balistics mathamatician has not been able to do...
I would never doubt his opinnion on what kills elephants, to do so would be the ultimate in arrogance...His field experience was simply beyond anything we can imagine today. I have never found anything he said to be out of line including his choice of rifles and cartridges.
Posts: 42554 | Location: Twin Falls, Idaho | Registered: 04 June 2000
My! Aren't the good ol' boys infatuated with John Taylor!
Taylor KO values are BS!
My gosh! Sure, for the solid, a heavier bullet of faster velocity and greater caliber will be more likely to stagger jumbo with a noggin shot, than will the slower, lighter, smaller diameter bullet.
You don't have to be a rocket scientist to figure that one out.
That is all the TKO says.
It is kind of common sense, eh?
Let us just call a spade a spade. The TKO is mumbo jumbo, an old poacher's parlor game. Total BS of no practical use except for making more BS, and giving an old poacher something to write BS about.
Posts: 28032 | Location: KY | Registered: 09 December 2001
You sure get crabby working the night shift, don't you?
And, hey, I have the title around here for being the crabby, critical, and cynical old man.
The problem with any indice is that in the field things sometimes don't work as they are suppose to, whether it is Taylor's or whoever's. The effort to define it is valiant and worthwhile, but I will never see enough field experience to prove one better than another.
And when you shoot a buff or elephant with the big gun and they don't even blink much less flinch, and give you that "FU" look, what does any indice really mean?
Will, forgive him, he has a acute case of assi-idas, a common desease among old hunters, it is when the nerves in the eye get crossed up with the nerves in the a$$ and that of course gives one a sh--ty outlook on life....
He's ticked cuz Taylor shot more and bigger elephant that he has, and never lacked fer wimmen in camp!!
Posts: 42554 | Location: Twin Falls, Idaho | Registered: 04 June 2000
Dagga, If you want an accurate killing formula, try the Atkinson formula, Use a postal scale to weigh the loaded round, the big dog sleeps on the poarch...no BS with this one.
Posts: 42554 | Location: Twin Falls, Idaho | Registered: 04 June 2000
Ho Ho Ho. The inconsistencies and unpredictability of the critter factor (too complex to model) is indeed what makes all "indices" just so much BS, the TKO included.
Posts: 28032 | Location: KY | Registered: 09 December 2001
quote:Originally posted by Atkinson: Will, forgive him, he has a acute case of assi-idas, a common desease among old hunters, it is when the nerves in the eye get crossed up with the nerves in the a$$ and that of course gives one a sh--ty outlook on life....
He's ticked cuz Taylor shot more and bigger elephant that he has, and never lacked fer wimmen in camp!!
Hey Ray - we call a similar illness here in Alaska "optirectititis" - same result, sh-ty view of life - very common in late December, early January - supposedly caused by the shortness of daylight during the winter - the only known cure is to go hunting somewhere far south of here (or fishing, works just as well) - KMule
Posts: 1300 | Location: Alaska.USA | Registered: 15 January 2002
Mick, Does your puzzlement refer the rumors about Pondoro's sexual orientation?
How about Pondoro wandering around wearing only a turban and sandals on his Mozambique ivory poaching trips?
Well, he must have been AC/DC, because Will claims to be the son of John Taylor and a native woman of Mozambique.
Ray, as usual is murdering the English language, and KMuleinAk is doing no better. My view of the TKO is actually called "coprobovoscopy." I see it as BS.
Posts: 28032 | Location: KY | Registered: 09 December 2001
quote:Originally posted by DaggaRon: Mick, Does your puzzlement refer the rumors about Pondoro's sexual orientation?
How about Pondoro wandering around wearing only a turban and sandals on his Mozambique ivory poaching trips?
Well, he must have been AC/DC, because Will claims to be the son of John Taylor and a native woman of Mozambique.
Ray, as usual is murdering the English language, and KMuleinAk is doing no better. My view of the TKO is actually called "coprobovoscopy." I see it as BS.
hey there doctor ron - it is a joke, in reference to what some call "cabin fever" - you lived in Alaska, yes? a joke, nothing more - good luck on your upcoming hunt KMule
Posts: 1300 | Location: Alaska.USA | Registered: 15 January 2002
quote:Originally posted by Wendell Reich: ... a larger diameter bullet will cause more damage, thus the credit given to the diameter in Taylors calculations.
You could have a projectile that weighs 500 grains that is as big around as a needle ... it would be 5 feet long. You can see how this would not cause such terrible results when fired into an Elephant. It would pass through him and he might not even know he was shot!
Sure, it is a ridiculous and exagerated situation, but you can see my point.
Right. But a more interesting case -- because it fits actual rifles and bullets -- would be a comparison of, say, a 150 grain .264 projectile at 2800 f.p.s., with a 150 grain .30 caliber projectile at exactly the same velocity. Both would have exactly the same kinetic energy. Given the way Taylor calculates his KO factor, the .30 caliber projectile would have a higher number. But would it really knock-out or kill any better?
Another example, based on existing rifles and bullets, would be 350 grain .375 bullet at 2400 f.p.s., versus a 350 grain .458 bullet at exactly the same velocity. Which is likely to give better penetration and knock-out?
In both of my hypothetical cases, the smaller diameter bullet would have considerably higher sectional density than the larger diameter one. Yet Taylor does not take that into account, even though sectional density is a major factor in penetration.
[ 05-02-2003, 18:53: Message edited by: LE270 ]
Posts: 5883 | Location: People's Republic of Maryland | Registered: 11 March 2001
I firmly belive in the TKO formula. Back in my college pitching days I could put one over the plate at 82mph, or about 120fps. Keep in mind that's a 2965 cal 2187.5 grain projectile.
Let's see, 2.965 x 2187.5 x 120 fps / 7000 = 111 TKO
That's almost twice the TKO of a 416 Rigby!
I know the sectional density is a bit low, but with this much 'bullet' diameter I expect the shock effect to more than make up for any perceived lack of penetration.
Next trip I plan to use the above load for buff and stick to the change up (45mph, or 66 fps) and curveball for plains game and thin skinned critters.
Bob, Wink when you say that! OK, at least remove your tongue from cheek and accept my congratulations for this excellent illustration of Taylor KO coprobovoscopy. Cheers!
Posts: 28032 | Location: KY | Registered: 09 December 2001
quote:Originally posted by Omnivorous Bob: I firmly belive in the TKO formula. Back in my college pitching days I could put one over the plate at 82mph, or about 120fps. Keep in mind that's a 2965 cal 2187.5 grain projectile.
Let's see, 2.965 x 2187.5 x 120 fps / 7000 = 111 TKO
That's almost twice the TKO of a 416 Rigby!
Yeah, but they say here that the Taylor formula works only with solids. So you're going to have to get some steel-jacketed lead-core baseballs for this. Maybe Woodleigh will make them for you if you order a sufficient quantity.
[ 05-05-2003, 06:08: Message edited by: LE270 ]
Posts: 5883 | Location: People's Republic of Maryland | Registered: 11 March 2001
quote:Originally posted by Atkinson: Dagga, If you want an accurate killing formula, try the Atkinson formula, Use a postal scale to weigh the loaded round, the big dog sleeps on the poarch...no BS with this one.
Can't argue with that, especially when weighing a .416 Rig and a .404 J. About the same, but one IS bigger than the other - no BS .
Posts: 2272 | Location: PDR of Massachusetts | Registered: 23 January 2001
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