Taylor Knock Out (TKO) Scale - The Firearms Forum

mesinge2 · 03-02-2010, 11:17 PM

I thought some people might like this data. I computed it based on the factory released velocity information with their corresponding barrel lengths during their tests.

Name: TKO Scale Compairsons.jpg
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Name: TKO Scale Compairsons.jpg
Views: 1334
Size: 442.2 KB

Added at request of steve4102 Corbon Self-Defense 10mm Auto 165 Grain JHP's TKO is 11.59, impressive

The formula used in the John "Pondoro" Taylor Knock Out (TKO) Scale for measuring power of calibers. Developed by an African hunter named John "Pondoro" Taylor. Basically, you multiply diameter of bullet in inches times muzzle velocity times bullet weight in grains divided by 7,000.

P.S. the 25 suprised me

petesusn · 03-03-2010, 05:18 AM

Maybe I'm missing something here but I don't need a mathamatical formula to tell me that the 500 Mag is more powerful than the 454 which is more powerful than the 44 Mag ect, ect. Give me energy figures (with different loads for the same caliber) for 10, 15, 25 yards and I'll be better able to figure what's able to stop a man, a rabid dog, a rhino, or whatever the best. Now I'm not knocking your chart. For some it might be good info but for me it's telling the obvious.

steve4102 · 03-03-2010, 06:44 AM

What, no 10MM Auto??

ofitg · 03-03-2010, 04:31 PM

mesinge2, you can really open a can of worms with this thread. As far back as I can remember, people have debated various methods to calculate a load's efficacy.

I hadn't heard about the Taylor KO scale until now.... so, how does the Taylor method handle the difference between, say, a 9mm 124gr JHP vs. a 9mm 124gr FMJ? Do you assume that the JHP has expanded to some specific diameter, and then plug that number into the formula?

mesinge2 · 03-03-2010, 05:39 PM

I don't think it factor's in bullet design at all. Which is unfortunate.

As for the 10mm, I just forgot sorry. I added the 10mm to the OP

jdon72 · 03-03-2010, 06:39 PM

Hmmmm...don't know about this one. Most of it is common sense. The bigger the cal, the more knock down per-sey. The 357 short is not as powerful as the 9mm. I would say the reverse. But that is MOP.

J

ofitg · 03-03-2010, 06:52 PM

The TKO method reminds me of the old Hatcher Relative Stopping Power formula :

RSP = M * V * A* F

M = bullet weight in pounds (ie, grain weight / 7000)

V = velocity in ft/sec

A = frontal area in square inches

F = factor which varies with bullet shape. This factor ranged from 0.9 for jacketed round nose slugs, up to 1.25 for lead wadcutters.

Hatcher's formula doesn't account for expanding bullets either.... it was the result from some U.S. Army tests conducted in 1904. Expanding handgun bullets were unheard of back then.

mesinge2 · 03-03-2010, 07:04 PM

Quote:

The 357 short is not as powerful as the 9mm. I would say the reverse. But that is MOP.

I checked this, the reason is because the 9mm was tested in a 4 inch barrel and the 357 short was tested in a 2" barrel; hence the difference.

steve4102 · 03-04-2010, 07:58 AM

My calculations of the 10MM Auto are a bit different.

180gr bullet X .400 dia. X 1287fps / 7000 = 13.24 TKO

1287fps is per Hodgdon data, I run 9.2gr of Longshot to 1305 avg fps.

Alpo · 03-04-2010, 08:14 AM

If it was developed by an African PH, I would guess it has nothing to do with pistols, but was developed for dangerous game rifles. That would explain why bullet design isn't factored in. It doesn't matter. You use solids.

ofitg · 03-04-2010, 11:20 AM

If you like the "mathematical" approach for predicting handgun bullet effectiveness, you might enjoy the book Street Stoppers, written by Marshall & Sanow. They compiled "one shot stop" probabilities for more than a hundred different loads, based upon thousands of actual police shooting reports. The book also contains data from bullet tests in 10% ordnance gelatin, and promotes a mathematical formula developed by a guy named Fuller.

If you're a REAL glutton for punishment, I might suggest the book Bullet Penetration, written by Duncan MacPherson. This book advances the views of the International Wound Ballistics Association.... very scholarly, but the math gets over my head in places.
The IWBA thinks that the best predictor for bullet effectiveness is the permanent crush cavity created in 10% ordnance gelatin, providing that the bullet penetrates at least 12 inches..... and for mathematical purposes, any penetration over 15 inches is regarded to be "15 inches"..... they figure that the average bad guy is only 15 inches thick, so any penetration beyond that depth is irrelevant.

The good news is, the gelatin tests in the Marshall-Sanow book include the data for permanent crush cavity (and penetration), so you can use those numbers for the IWBA approach if you want to.

mesinge2 · 03-04-2010, 04:30 PM

Quote:

My calculations of the 10MM Auto are a bit different.

180gr bullet X .400 dia. X 1287fps / 7000 = 13.24 TKO

1287fps is per Hodgdon data, I run 9.2gr of Longshot to 1305 avg fps.

The 165 grain bullet in my calculations is the reason for the lower TKO value

03-02-2010, 11:17 PM	#1
mesinge2 Senior Member Join Date: Dec 2009 Location: Central Florida Posts: 538	Taylor Knock Out (TKO) Scale I thought some people might like this data. I computed it based on the factory released velocity information with their corresponding barrel lengths during their tests. Added at request of steve4102 Corbon Self-Defense 10mm Auto 165 Grain JHP's TKO is 11.59, impressive The formula used in the John "Pondoro" Taylor Knock Out (TKO) Scale for measuring power of calibers. Developed by an African hunter named John "Pondoro" Taylor. Basically, you multiply diameter of bullet in inches times muzzle velocity times bullet weight in grains divided by 7,000. P.S. the 25 suprised me __________________ NRA Certified Instructor "A strong body makes the mind strong. As to the species of exercise. I advise the gun. While this gives moderate exercise to the body, it gives boldness, enterprise, and independence to the mind ... Let your gun therefore be your constant companion of your walks." 1785, Thomas Jefferson. --> Last edited by mesinge2; 03-03-2010 at 05:42 PM..

03-03-2010, 05:18 AM	#2
petesusn Senior Member Join Date: Sep 2009 Location: San Joaquin Valley, Ca. Posts: 614	Re: Taylor Knock Out (TKO) Scale Maybe I'm missing something here but I don't need a mathamatical formula to tell me that the 500 Mag is more powerful than the 454 which is more powerful than the 44 Mag ect, ect. Give me energy figures (with different loads for the same caliber) for 10, 15, 25 yards and I'll be better able to figure what's able to stop a man, a rabid dog, a rhino, or whatever the best. Now I'm not knocking your chart. For some it might be good info but for me it's telling the obvious. __________________ Self Defense: A basic human right The 2nd Amendment, ratified in 1787, refers to the National Guard, which was created 130 years later, in 1917. A man who may be asked in this century what he did to make his life worthwhile...can respond with a great deal of pride and satisfaction, "I served in the U. S. Navy." John F. Kennedy VFW Life Member

03-03-2010, 06:44 AM	#3
steve4102 Former Guest Join Date: Jan 2006 Location: Minnesota Contributor Posts: 2,760	Re: Taylor Knock Out (TKO) Scale What, no 10MM Auto??

03-03-2010, 04:31 PM	#4
ofitg Advanced Senior Member Join Date: Feb 2010 Contributor Posts: 1,447	Re: Taylor Knock Out (TKO) Scale mesinge2, you can really open a can of worms with this thread. As far back as I can remember, people have debated various methods to calculate a load's efficacy. I hadn't heard about the Taylor KO scale until now.... so, how does the Taylor method handle the difference between, say, a 9mm 124gr JHP vs. a 9mm 124gr FMJ? Do you assume that the JHP has expanded to some specific diameter, and then plug that number into the formula?

03-03-2010, 05:39 PM	#5
mesinge2 Senior Member Join Date: Dec 2009 Location: Central Florida Posts: 538	Re: Taylor Knock Out (TKO) Scale I don't think it factor's in bullet design at all. Which is unfortunate. As for the 10mm, I just forgot sorry. I added the 10mm to the OP __________________ NRA Certified Instructor "A strong body makes the mind strong. As to the species of exercise. I advise the gun. While this gives moderate exercise to the body, it gives boldness, enterprise, and independence to the mind ... Let your gun therefore be your constant companion of your walks." 1785, Thomas Jefferson.

03-03-2010, 06:39 PM	#6
jdon72 V.I.P. Member Join Date: Feb 2009 Posts: 340	Re: Taylor Knock Out (TKO) Scale Hmmmm...don't know about this one. Most of it is common sense. The bigger the cal, the more knock down per-sey. The 357 short is not as powerful as the 9mm. I would say the reverse. But that is MOP. J

03-03-2010, 06:52 PM	#7
ofitg Advanced Senior Member Join Date: Feb 2010 Contributor Posts: 1,447	Re: Taylor Knock Out (TKO) Scale The TKO method reminds me of the old Hatcher Relative Stopping Power formula : RSP = M * V * A* F M = bullet weight in pounds (ie, grain weight / 7000) V = velocity in ft/sec A = frontal area in square inches F = factor which varies with bullet shape. This factor ranged from 0.9 for jacketed round nose slugs, up to 1.25 for lead wadcutters. Hatcher's formula doesn't account for expanding bullets either.... it was the result from some U.S. Army tests conducted in 1904. Expanding handgun bullets were unheard of back then.

03-04-2010, 07:58 AM	#9
steve4102 Former Guest Join Date: Jan 2006 Location: Minnesota Contributor Posts: 2,760	Re: Taylor Knock Out (TKO) Scale My calculations of the 10MM Auto are a bit different. 180gr bullet X .400 dia. X 1287fps / 7000 = 13.24 TKO 1287fps is per Hodgdon data, I run 9.2gr of Longshot to 1305 avg fps.

03-04-2010, 08:14 AM	#10
Alpo Advanced Senior Member Join Date: Feb 2007 Location: NW Florida Posts: 8,662	Re: Taylor Knock Out (TKO) Scale If it was developed by an African PH, I would guess it has nothing to do with pistols, but was developed for dangerous game rifles. That would explain why bullet design isn't factored in. It doesn't matter. You use solids. __________________ Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297 I always take precautions. Beware the Evil Bullet Fairies.

03-04-2010, 11:20 AM	#11
ofitg Advanced Senior Member Join Date: Feb 2010 Contributor Posts: 1,447	Re: Taylor Knock Out (TKO) Scale If you like the "mathematical" approach for predicting handgun bullet effectiveness, you might enjoy the book Street Stoppers, written by Marshall & Sanow. They compiled "one shot stop" probabilities for more than a hundred different loads, based upon thousands of actual police shooting reports. The book also contains data from bullet tests in 10% ordnance gelatin, and promotes a mathematical formula developed by a guy named Fuller. If you're a REAL glutton for punishment, I might suggest the book Bullet Penetration, written by Duncan MacPherson. This book advances the views of the International Wound Ballistics Association.... very scholarly, but the math gets over my head in places. The IWBA thinks that the best predictor for bullet effectiveness is the permanent crush cavity created in 10% ordnance gelatin, providing that the bullet penetrates at least 12 inches..... and for mathematical purposes, any penetration over 15 inches is regarded to be "15 inches"..... they figure that the average bad guy is only 15 inches thick, so any penetration beyond that depth is irrelevant. The good news is, the gelatin tests in the Marshall-Sanow book include the data for permanent crush cavity (and penetration), so you can use those numbers for the IWBA approach if you want to.