TKO, Thornily Formulas

Discussion in 'Firearms' started by Ahnkochee, Jul 8, 2011.

  1. Ahnkochee

    Ahnkochee Bushmaster

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    The thread on best bear defense firearms reminded me to think of this- Comparing 30-06 to 454 Casull etc. energy figures, etc.
    I have never liked using muzzle energy figures alone as the sole source of information when comparing cartridge effectiveness or determining suitability for hunting game. Muzzle energy takes into consideration only the weight and velocity of projectile.
    John (Pondoro) Taylor a famous professional hunter from East Africa came up with respected formula which also takes into account the diameter of the projectile which to me more accurately shows the potential of a cartridge.
    Peter Thorniley a hunter with extensive hunting experience in both North America, and Africa designed his formula years ago which calculates via a relative stopping power quotient the amount of gun and load necessary to cleanly take a game animal under all conditions.
    No formula is perfect since bullet design is not taken into consideration but I prefer the Taylor, and Thornily formulas over straight energy figures in more accurately determining a cartridge's potential, and in comparing cartridges for the field.
    I have attached links to the Beartooth Bullets site for your perusal. Punch in your favorite load numbers and compare them. Have fun. ;)

    Taylor Knock Out Power Calculator: http://www.beartoothbullets.com/rescources/calculators/php/taylor.htm

    Thornily Relative Stopping Power Calculator: http://www.beartoothbullets.com/rescources/calculators/php/thornily.htm

    Foot Pounds Energy Calculator: http://www.beartoothbullets.com/rescources/calculators/php/energy.htm
     
    Last edited: Jul 8, 2011
  2. Ahnkochee

    Ahnkochee Bushmaster

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    Example

    30-06: 180 grains @ 2700 FPS = 2913 foot pounds energy
    454: 300 grains @ 1700 FPS = 1926 foot pounds energy
    44mag: 300 grains @ 1400 FPS = 1306 foot pounds energy
    12ga slug: 601.56 grains @ 1502 FPS = 3,014 foot-pounds energy


    30-06: 180 grains @ 2700 FPS = A Thornily Relative Stopping Power Scale of 109
    454: 300 grains @ 1700 FPS = A Thornily Relative Stopping Power Scale of 142
    44mag: 300 grains @ 1400 FPS = A Thornily Relative Stopping Power Scale of 114
    12ga slug: 601.56 grains @ 1502 FPS = A Thornily Relative Stopping Power Scale of 344


    30-06: 180 grains @ 2700 FPS = A Taylor KO Value of 21
    454: 300 grains @ 1700 FPS = A Taylor KO Value of 33
    44mag: 300 grains @ 1400 FPS = A Taylor KO Value of 26
    12ga slug: 601.56 grains @ 1502 FPS = A Taylor KO Value of 94


    30-06 wins in foot pounds energy but factoring in the diameter of projectile the .454 Casull wins, and the 44 mag is second using the Taylor, and the Thornily formulas.
    The 30-06 does have the accuracy advantage from a distance but up close and personal the advantage disappears, and the slower follow-up shots also a disadvantage whereas a double action revolver can get more shots off quicker when it counts.
    The 12 gauge shooting 1-3/8oz. 3" Brenneke slugs wins every formula so the best choice if you don't mind lugging it around. :4:
     
    Last edited: Jul 9, 2011
  3. Arizona-Hermit

    Arizona-Hermit Scout

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    Interesting perspective.
     
  4. Geneh

    Geneh Supporter Supporter

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    I think the TKO-type calcs are worth looking at. We've been thinking more of TKO in our family and veering away from "flat and fast" ballistics. The only experience so far is limited and anecdotal at best.

    Dad used a 30-06, and I have dropped a lot of Whitetails with the same rifle. (that's going on 45 years for that rifle) but he alwasy said he missed the 35 rem. Heavy and slow seems to retain more energy once it meets resistance than light and fast.

    A friend of mine used his 45 cal round ball muzzle loader one year and that deer dropped in it's tracks, not even a flinch.

    My son last year used 12 ga slug, and the deer was jolted out of it's tracks quite a bit. Interesting the size (small) and shot placement (the head, of all places) was very close to one I took with the '06 a couple years earlier. Mine dropped, his was moved.
     
  5. Pinebaron

    Pinebaron Curmudgeon

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    There is value in this. I have an FBI report that discusses stopping power. It talks about what characteristics are important. They are:
    1. Shot placement. This is the most critical component.
    2. Penetration. The bullet must be able to reach the organs aimed for.
    3. Permanent Wound Channel. This is what causes tissue destruction and allows for rapid bleed out. Because organs are elastic, temporary would channels are not considered reliable.

    The Taylor/Thornily formulas seem to bear this out.

    I also agree with you that using muzzle energy calculations does not impart a clear picture of bullet performance.

    One other thing to consider though is these formulas should be used at terminal ballistics and not at the muzzle because bullet performance varies at different ranges for different cartridges (think 12ga. slug at 300 yards).
     
  6. GreyOne

    GreyOne Elder Lifetime Supporter

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    The Taylor formula is quite similar to Hatchers Formula for handguns , and a thing I learned early on is that such formulae are rather limited when comparing things far apart in either bullet weight or velocity.

    Comparing a 30-06 to a 454 Casull tends to fall into that category. :) Bullet expansion, shot placement, actual penetration, etc. are all of significance.

    The Hatcher Forumula and Cooper's Short Form are both interesting for handguns.

    The FBI report if it is the one I am familiar with, was based on their "Computer Man " simulation. It was found to be flawed, as they had "weighted" the results to favor .355 bullet diameter. :)

    All of the formula systems can be worth looking at, but in the end, none of them seem able to give valid real world predictabilty at a level that would be considered scientifically valid.

    I think there are certain minimum levels for a projectile weapon to be effective, and they vary according to purpose.

    Cooper thought a handgun should be at least a .40 caliber, at least 1000 FPS with a 180 grain bullet to be good against 2 legged problems.

    I don't have Pondoro's book at hand, and cannot remember his exact standards, but I think he found a 375 H&H acceptable for most dangerous game.

    For US game- Whitetail, Muley's, Elk, Black Bear, and such, a 30 caliber projectile at 2200 fps (30-30 Win) is about a good starting place.

    For Grizzly bear, I know that most Alaskan guides and hunters considered for years that the 375 H&H was about ideal.

    Formula / theory comparisons make for interesting discussions, but the very best way to choose is to ask those who are living and hunting that game and area on a regular basis. If a large percentage of them recommend the same thing, you know it would be a good choice.
    :)
     
  7. GreyOne

    GreyOne Elder Lifetime Supporter

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  8. Pinebaron

    Pinebaron Curmudgeon

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    Actually this report more favored the .40 and larger calibers. One of the factors of the report stated that a LARGE permanent wound channel was important.

    The dichotomy we often see are cartridges like the .45-70 vs. .375. Both are accepted as big game cartridges suitable for large bear but one is the heavy and slow and the other is lighter and zippier. In fact the .45-70 has been used to take elephant and other African dangerous game.
     
  9. Pinebaron

    Pinebaron Curmudgeon

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    Quote from that report, last paragraph page 16. "Given desirable and reliable penetration, the only way to increase bullet effectiveness is to increase the severity of the wound by increasing the size of the hole made by the bullet...Of those that will penetrate, the edge is always with the bigger bullet."

    It appears that the report does indeed favor larger caliber bullets.

    Penetration is also important with the report stating that minimum penetration should be no less than 12 inches. But by far, the most critical aspect is still shot placement.
     
  10. rockett88s

    rockett88s Scout

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    Hmmmmnnn...

    Is it agreed that all of the above formulas are predicated on the effect of one single projectile? If so, is this flawed reasoning? Most of these formulas were developed to advance or describe the relative efficiency of various calibers vs. other calibers. Such conjecture leads to the never-ending arguments that one caliber is better than another. I find such reasoning to be flawed. It is not the caliber that wins the fight. it is the tactics. Proper tactics would dictate firing in rapid, controlled bursts, whether in a defensive or a hunting situation. I'd like to see the tests that show the relative efficiency of firing three 180 gr 30-06 hollowpoints, vs. four 300 gr ,454 Casull flat points. That test report would be some interesting reading...
     
  11. GreyOne

    GreyOne Elder Lifetime Supporter

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    I am of the old school- One shot, One kill.

    Firing multiple shot bursts is indeed a useful _military_ tactic, but for most of us, selective fire weapons are not an option, and semi auto only is no faster than a revolver (at least for the fist 6 shots).

    Often, in both hunting and situations like self defense, the first shot may be all you get.
    Either it is good, or you are too late.

    Old story about the Maine guide who said "One shot, deer; two shots, maybe deer; three shots, no deer."

    I have found a lot of truth in that. YMMV.
     
  12. Malamute

    Malamute Guide

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    Multiple accurate shots on game aren't realistic in any hunting situation I've been in. It would also be wasteful of meat. One shot should be enough with an adequte gun and load for hunting purposes. Most experience hunters also say that the first shot delivers the most effect to large animals, and subsequent shots don't seem to have anywhere near the effect once the animal has it's adreneline going after the first hit. In a defensive situation, one shot may be enough, but placement is likely to be problematic, so we continue to shoot so long as needed or possible. Still, one good shot should do the job if placed right.

    I've been a fan of the Taylor formula, but realized it was oriented too much towards diameter. The 12 ga slug rates higher than the375 H&H or 458 win mag, which I simply don't agree with. Another factor, I read Taylor's book. In it, he mentioned that it wasn't very good at comparing different types of bullets, it's original use was deteriming the knockout value of a particular bullet when used on head shots on elephants, not body shots on various animals, and different types of bullets. The factor number was the relative length of time an elephant would be knocked out with an imperfect head shot, in other words, how long you had to finish the job. Taylor had had elephants get up that were head shot, and seemed to miraculously come back to life, as had other hunters. The larger and heavier the bullet, the longer they were knocked out. It's an interesting formula, but has no way to compare expanding bullets or flat points against round nose etc, all of which make a difference in real life game shooting, especially on bears and other American game. Taylor admitted this, and didn't consider it good for general hunting comparisons on different game.

    Someone mentioned soemthing about several experienced users recomending calibers. This seems like a good idea. Single animals, even a handful with any perticular caliber or loading doesnt give the same picture as more extensive field experience. I just don't know of any formula that takes all the factors into consideration to be able to make reliable preditctions on various loads and bullet types. As an example, one gunsmith I know has a client that is a guide in Alaska, and has used various large caliber rifles. His favorite is a 300 supermag of some sort with premium bullets. He contends that it gives him more results per shot than anything else he's used on bears. 30 caliber rifles dont rate that high on most charts, especially compared to the 375 (Weatherby or Rem supersize?), 416 Rem and other larger magums, but his hands on experience tells him it's what he wants to use to back clients up.
     
    Last edited: Jul 9, 2011
  13. rockett88s

    rockett88s Scout

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    Thanks Mal...

    You and G-1 seem to say things in a manner that I can get my mind around.... I appreciate that! My ragged copy of Taylor's book, "African Rifles and Game" is beyond my reach in one of my ex wives' basements... It's definitely one of my favorite reads, and I'm looking for another copy... They're pretty rare, but well worth the effort...

    My point with Multiple shots is geared towards defensive scenarios... and I still think rapid bursts... multiple shots, hammer pairs double or triple taps... is more effective than hoping a single bullet will do the job.

    I heard the "one shot , two shots, three shots line first hand from the Ol' Swede up on a logging road outside of Jackman... I had fired the three shots, and he was surprised to find a very tasty Bull Moose dead in a clearing, right next to the road.... Much luck capped with enough technical dexterity to get the job done... we feasted well that night, and a dozen years later I'm still referred to as "Three Shot Charlie, the Lucky Flatlander"... While I always strive for a clean one shot kill, I never hesitate to fire a following shot to anchor the prey.

    Lots of great info in those links, too...
     
  14. GreyOne

    GreyOne Elder Lifetime Supporter

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    Here is a link to a page on Taylor's book- the first two were $42 and $45, plus S&H. AbeBooks is a handy place to find out of print specialty books.

    <http://www.abebooks.com/servlet/SearchResults?an=John+Taylor&kn=Africa,+Rifles&sts=t&x=56&y=5 >

    As for the mutiple shots for defensive scenarios, I know that is how the current tactical training and thinking is oriented. We shoot that way for qualifications. I am skeptical though. If the first shot is not a hit, odds are not good for the rest of your "burst". I want that first shot to hit, followup shots are fine if needed, but the current trend is more and more towards spray and pray tactics, and I think that is a mistake. JMHO/ YMMV. :)
     
  15. Ahnkochee

    Ahnkochee Bushmaster

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    Amen, TKO formula definitely not perfect failing to take bullet design into account for one thing but still good for comparing cartridges. I prefer the 375 H&H over just about any other cartridge for hunting North America or Africa. From deer to Cape Buffalo, and all bears I would feel confident with the 375 H&H. This another one of my dream rifles in a CRF Mauser action with 3 position bolt safety and laminated stock, and a rear three leaf express sight. :4:
    Very close second (due to cost) a SxS double rifle in 9.3x74R. :4::4:
     
  16. rockett88s

    rockett88s Scout

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    Hey G-1 , many thanks for the link! LOL... ask any of the guys on my team... ONLY hits count! Loud noises do not put meat on the table , nor do they resolve tactical situations...
     
  17. Ahnkochee

    Ahnkochee Bushmaster

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    For 35+ years I've been hunting with my 44 mag Marlin, and also 30/30s from several rifles (94 Win., 170 Savage, 340 Savage, 336 Marlin). On paper 44 mag vs 30/30 as far as muzzle energy, and energy at 50, and 100 yards the 44 mag did not look impressive in comparison to the 30/30. In actual field performance on game I found the 44 mag to be much superior in dropping the game (mostly wild pigs, with wild goats, and deer in the mix) never requiring a follow up shot nor tracking of hit animal, they just dropped right there (hammer of Thor :4:). Now with comparable shot placement I have had to track game hit with a 30/30 though never far, and never loosing any. Something else besides ME figures had to explain this. TKO & Thornily formulas seem to do a good job at this.
     

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