Debunking the TKO myth

[Kachok]

I have seen a trend start to re-emerge, the stupid TKO factor that died off years ago due to complete lack of scientific basis is rearing it's ugly head again, and is starting to be talked about like hard fact by many in this community. I decided to throughly look at it again and see if there is any possable way this could help us hunters and riflemen determine the true killing power of our tools. The ugly truth is this is just as much a fairy tail now as it was when it was first written. I have compiled some actual tests and figures to demonstrate that this in not remotly a true messure of killing power. Here are a few errors.
The 1st error is that we North American hunter try to apply this to soft tissue damage when John himself admited this was for headshots only. "Both barrels from a .600 in the belly (of an elephant) will have little more apparent effect than a single shot from a .275 in the same place." (African Rifles and Cartridges, Taylor. Page 59). TKO was a guage of the effect of a headshot that missed the brain or faild to penatrate nothing more.
2nd Taylor’s use of bullet diameter, instead of cross sectional area, is in fact mathematically incorrect, as a bullet having twice the diameter to a smaller one has in fact more than twice the cross sectional area.
3rd this formula has nothing to do with modern expanding bullets, even the theory behind it involved deep penatrating solids.
OK enough with the techno bable and lets get to some real examples of what I am talking about. Lets do a comparison here, one with a real life example to back it up. A 12ga .70cal 437gr slug at 1513fps (TKO 66.12) vs a puney little 150gr 308 at 2846fps (TKO 18.79) according to the TKO factor the slug should make aprox 3.5 times more tissue damage then the 308 at point blank range right? Well in this experement performed by Dr. Fackler of the Letterman Army Institute of Research the 308 had a greater temporary wound cavity, permenent wound cavity and deeper penatration then the huge Foster slug, this example shows not only did the TKO factor not hold up but the oposite was in fact true. Tissue stretching beyond it's ability to "bounce back" is the result of strain not KE or caliber. Even the tiny little 30-30 exibited better terminal ballistics then the 12ga in this experement. http://www.chuckhawks.com/energy_transfer.htm "Stresses cause damage only if they strain body tissues above their elastic limits."

Sorry for being so long winded but detailed scientific information is always needed to debunk myths that people have been tought for many years, it just becomes ingrained in our psyche. Hope everyone found this educational.

 

[Jim Watson]

Doc Fackler shot a lot of elephants, did he?
Maybe ol Chuck has, I don't know.

 

[Kachok]

I have also compiled a whole list of wrightings from perfosional ballisticians and very experenced hunter that agree that the TKO formula is highly inaccurate. I have yet to find one that would support it. Except for maby John himself LOL. No I am sure that Chuck Hawks has not hunted many elephants but Walter D.M. Bell did and he used nothing but rifles that the TKO formula would rate as pathetic

 

[Pigspitter]

Realistically, if the force of a bullet hits an animals skull with the force of boxing knockout punch it is possible to KO an animal. This depends on the mass of the animals head and the bullet used, but it is possible just unlikely. To put it in perspective, a 17HMR has about 250ft/lbs of force at the muzzle which is about the same as an average persons strongest punch. Now imagine wearing a ring and punching somebody as hard you can in the side of the head when they least expect it. They might be knocked out, but they are definitely going to be seriously dazed.

Edit: About halfway through this article is some medical talk about the effects of missle wounds on a human skull/brain http://emedicine.medscape.com/article/343764-overview

 

[HOOfan_1]

Doc Fackler shot a lot of elephants, did he?
Maybe ol Chuck has, I don't know.

Are you trying to start a Chuck Hawkes meme for shooters to equal the Chuck Norris one?

 

[Kachok]

I would not argue the effectivness of the TKO formula in relation to marginal head shot knockouts seeing as I do not take headshots, but in terms of soft tissue damage it is nonsence pure and simple. Lerger caliber going in only makes a lager entry wound, which has nothing to do with the amount of damage you would do to the vitals. Modern hunting bullets expand quickly at high speeds, this makes them create wound canals vastly larger then the caliber of the bullet itself even larger then the expanded bullet. I have seen a 30-06 make a wound canal that stretched and split three sides of the ballistic gel block! Over 10" wide before it ruptured! TKO is like terminal ballistics for a caveman "Ug 45 cal bullet 45 cal hole ug" There is no accounting for the fact that a bullet at 2700fps in a fluid enviromant is a VERY dynamic event to say the least. I have seen a 25cal bullet leave an exit wound on a deer that would make you think a cannonball went through him!

 

[H&Hhunter]

Much of what was written by the classic elephant / big game hunters of the past is pretty much null and void given the development of modern expanding bullets. Except for the fact that we don't use modern expanding bullets when elephant hunting. We still use solids that perform much the same as they did 100 years ago.

When is comes to hunting anything but elephant I agree that much of the advice of old isn't very relevant as we now have expanding bullets which we can count on to not fail for the most part.

With elephant one axiom is still very true and modern day elephant hunters will tell you this over and over. If you are hunting elephant in thick cover in tight situations bigger and heavier is better as an elephant will turn from a heavy striking blow where a lighter caliber won't make him turn with identical shot placement.

Most super experienced elephant hunters today prefer to use a rifle of .50 cal or greater. the .500 NE seems to be the level at which you can count on a turn or a knock down from a frontal shot even if you miss the brain.

Buy Buzz Charleton's DVD on elephant hunting. It has some dramatic footage of the difference in noticeable reaction between even a .470 and a .500 NE the .470 throwing a 500 gr .474 diameter round @ 2150 and the .500 throwing a 570 gr .510 diameter bullet at about the same velocity. There is a huge difference between the two on a frontal shot on a big bull elephant. On a cow not so much as they have a much smaller head and body. A big cow is roughly 2/3rds the size of a big bull.

Here is link to that DVD it is the best no BS instructional hunting vid I've ever seen with some spectacular footage.

http://www.amazon.com/Hunting-Afric...0LC2/ref=sr_1_1?ie=UTF8&qid=1293070502&sr=8-1

 

[Kachok]

Even when headshots on elephant is the consideration remember the most sucessful elephant hunter in human history Walter Bell hunted them with 6.5mms and 7mm Mausers. He said that larger calibers made no difference, if you hit the brain they would go down very quickly, if you did not you have to shoot again anyway. He tried the 450NE but went back to his 7mm John Taylor was an experenced big game hunter no doubt, but his level of experence with elephants was nothing compared to Bell.

 

[Ridgerunner665]

One of my 45-70 loads...ain't no 30-06 around that can do it any better.



Bullet Weight (in grains) :..........405
Bullet Dia (in inches) :..............458
Powder weight (in grains) :........50
Bullet Velocity (i fps) :.............1,900 fps



Taylor Knock-Down Factor :...........50
Kinetik Energy (ft-lbs) :................3,244 ft. lbs.
Momentum (ft-lbs) :.....................110 ft. lbs.
Big Game OGW (BG-OGW) :...........1688 lbs.


30-06.....

Bullet Weight (in grains) :........180
Bullet Dia (in inches) :............308
Bullet Velocity (i fps) :...........2,700 fps

Taylor Knock-Down Factor :........21
Kinetik Energy (ft-lbs) :.............2,912 ft. lbs.
Momentum (ft-lbs) :..................69
Big Game OGW (BG-OGW) :.........956 lbs

 

[Ridgerunner665]

A very thorough bullet test with many "so called" premium bullets...notice which bullet made #1, and how many jugs it penetrated and exploded. (444 Marlin)

http://www.marlinowners.com/forums/index.php/topic,81274.30.html ...link goes to page 3 of the thread, but read it all...its a good read)

 

[Kachok]

Busting water jugs with a small varity of bullets is hardly a comprehensive ballistics comparison. Very heavy slower bullets especaly the flat point solids tend to have narrow but consistant wound canals, that is great for some things but delivering maxamum soft tissue damage to a deer or elks vitals is not one of them. Now don't get me wrong I LIKE big heavy bullets, if you read my head to head comparisons you will know that. They carry momentum and KE downrange better then smaller lighter ones and they tend to have more reliable terminal performance. But my likeing of big heavy bullets does not make the TKO factor any more true then the magic bullet theory.

 

[Ridgerunner665]

Now were getting somewhere...

Flat point solids...flat points that equal no more than 73% of the bullet diameter have proven time and again to be VERY devastating (you can find that on Marlin Owners too).

People have done extensive testing (not on water jugs either) to get the sweet spot...looking for tissue damage and ballistic coefficient... most have settled at 72% meplat diameter, myself and many others have seen these bullets nearly turn hogs and deer inside out (slight exaggeration, but only slight...pics on MarlinOwners)

Veral Smith, Marshall Stanton, Michael Reamy (I think I spelled his last name wrong), and others...these guys have brought cast boolits into the 21st century.

This never was about TKO or OGW...it was about clean kills and the mechanics involved in that.

There are speed brackets...points at which the rules change, depending on bullet shape, construction, caliber, sectional density.

 

[Kachok]

Flat point solids are the most efficient killers in the ballistics world. Not because they have a high TKO factor, but because they don't expend any of the bullets energy deforming + there is no more consistant performance then a bullet that does not have to do anything but keep on moving No they won't create the huge internal wound canals that liquifies the entire chest cavity, but with a good sized meplet will do plenty enough soft tissue damage to drop any deer that ever walked, sure you realisticly have to put up with a little more recoil to enjoy a big bore but they are just as effective now as they were 100 years ago. Another great thing is you don't ever have to worry about bullet malfunction. Cheap softpoints can under expand and pass clean through without causing any substantial tissue damage, or overexpand and blow apart before passing through the vitals, no such malfunctions on a high zinc alloy flat point. 100% full penatration is the name of the game.

 

[Ridgerunner665]

Not only deer and hawgs...elk, moose, and grizzly too.

Zinc alloy? Thats a new one...I'll take water quenched WW's with a dash of #8 shot at 21 BHN.

These bullets don't turn the insides to mush...but they will blow golf ball sized holes through anything up to buffalo. (any variety of buffalo)

 

[Kachok]

The thicker the game the better heavy solids are. They are way too much penatration to be the optimum deer round, but they still work for that aplacation as well. 450+gr HARD solids are know for passing through bison and water buffalo.

 

[Ridgerunner665]

We agree...

Now back to where you and I started...the 45acp does the same thing to deer (with proper bullets)

I'm not asking you or anybody else to deer hunt with a 45acp...what you choose to hunt with is entirely up to you and I will not belittle you for your choice.

All I'm saying is that the 45acp will kill deer quick and clean...if you put a hole through the right place.

Can we agree?

 

[Kachok]

Still don't bite on the 45ACP for one good reson. I have read a detailed study on the terminal performance of flat point solids and while they are not supposed to have perky super wide wound canals, they do get MUCH better performance at impact speeds above 1200fps, the 45ACP won't reach 850 fps with a heavy 250gr+solid much less carry that to a target 30-50 yards away. Not the worst choice in the world but if you really want to hunt with a handgun the 44mag is a MUCH better choice.

 

[Kachok]

If for some very odd reson I could not hunt with anything over 450 ft lbs I guess there would not be a better choice then a 45 cal w/heavy solids. I will give you that much. I just don't see the need seeing as I have several perfecly good rifles that will do the job much quicker and more humanly.

 

[Ridgerunner665]

It will get that speed (950) with cast bullets...and it carries that speed a long ways simply due to the fact that it is moving so slow.

Run a 255 grain bullet through a ballistics calculator at even 850 fps (you can get 950)...the ballistic coefficient is .190.

I think you'll be surprised at how very little velocity it loses even at 100 yards...

At 850 fps it loses 32 fps at 50 yards (818 fps)

At 950 fps it loses 42 fps at 50 yards (908 fps)...speed brackets, more air resistance

See the speed brackets I mentioned? Above 850 fps is one of them...sometimes less is more.

Above 1,200 fps...thats 45 Super, its awesome...and in another speed bracket.

 

[Ridgerunner665]

This is fun...but I'm gonna get off here and watch Human Target (love that show)

We can continue later if you want. Have a good night!

 

[Kachok]

I'll still skip the 45ACP Give me a 454 lever gun pushing 340gr flat solids to 1600 fps NOW we are talking That will out thump and out penatrate the hardend 12 ga slugs.

 

[Robert]

I had never even heard of this TKO thing until you posted this... I am really meh about the whole thing.

And when it comes to Dangerous Game hunting H&Hhunter's word is iron clad with me.

 

[Kachok]

For deer and hogs at realistic ranges though it is impossable to beat my 6.5x55 loaded with long and heavy 140gr bullets, it shoots flat loosing almost no speed or energy, it penatrates thick hog hides like a rugged syringe, then it rapidly expands creating a nasty wound canal that makes magnums green with envy I always get an exit wound ranging from golfball sized to a grapefruit sized crater. To top it off it is scary accurate, the recoil is very very mild and it is rather quiet too. Never had to track ANYTHING, no excuses, no complaints, just a bunch of meat in the freezer. That is why I don't but into the TKO because that little beast drops them quicker then any magnum slug I have ever used. It's tiny bore only gives it a 14 on the TKO meter, but they have been dropping every species of big game the world has to offer for well over a century now. Elephant, bison, moose, bear, they all fall to the tiny yet heavy 6.5

 

[H&Hhunter]

He tried the 450NE but went back to his 7mm John Taylor was an experenced big game hunter no doubt, but his level of experence with elephants was nothing compared to Bell.

Kachok,

Bell killed 1100 and some elephants 800 with his 7MM and 200 with his .303 and smattering of others with various calibers. Taylor's count was at least twice that number. Further more you are getting killing and stopping confused. Making a brain shot on a relaxed elephant in the open with a small caliber rifle is not such an amazing feat as one who hasn't done might imagine. The primary trick is knowing where the brain lies and how to route your bullet.

Thumping an enraged elephant at close range is an entirely different issue. You don't have time to precisely aim more than likely your shot is going to be a snap shot you will probably be moving when you shoot and in circumstance you need a sledge hammer of a round not a surgical pin prick because chances are even if you are a HIGHLY experienced elephant shooter you are going to miss the brain on your first shot. Heck on my first elephant I missed the brain on a standing still side brain shot at 40 yards. It is not as easy as you might think.

Bell hunted primarily old solitary bulls he wasn't hunting mixed herds like we do today and was occurring in the years after Bell's time. Mixed herds in thick country is without a doubt the most dangerous form of hunting there is period, end of story and the number of hunters/team members killed and severely wounded each year doing it is proof.

Remember there are modern day cropping officers who have killed WAY more elephant than Bell, Ron Thompson being one example with over 5,000 documented elephant kills he used a bolt gun in .458 WM. Richard Harland is another who has over 4,000 documented elephant kills. He was also a .458 man. Both of these guys speak of having killed multiple elephants with their issued FN rifles but only if the terrain was right. And remember both of these guys could make a brain shot on an elephant in their sleep. Only a fool ventures into thick jesse after elephant with a light caliber rifle. In fact I don't even like to hunt in elephant country without an adequate elephant stopper in my hands. I've been chased and harassed by elephant on several occasions it will change your perception about the subject of small calibers and elephant real fast.

If you get the chance read "The Last of the Ivory Hunters" By John Taylor he has a really flattering chapter about Bell in particular read pgs. 60 to 63.

 

[Freedom_fighter_in_IL]

While I TOTALLY agree with the TKO being bogus and unrelated to todays firearms, I also totally agree with H&H. I have hunted all over North America and Europe as well as a few other countries. Never have went on Safari in Africa because I am a meat hunter and not a Trophy hunter. I bring home my meat. Which is now limited to North America only nowadays. Never could from Africa but that is another subject. When going up against dangerous game, there is a HUGE difference between calm, rested, well aimed shots and a Crap your pants there is 8 tons of pissed off coming at you and only 35 yards away I for one want as close to a CANNON in my hand as I can possibly get.