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Shooting & Reloading - Mausers, Big Bores and others >> Big Bore Rifles
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hoppdoc
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STOPPING POWER-How to best measure it??
      #54326 - 07/04/06 05:21 AM

One of the real chewtoys hunters get into is the stopping power of their weapons.

I personally consider it the abiity to stop a attacking charge with a non-CNS shot. If the CNS can be hit routinely we would all be hunting with smallbores

Indeed with enough "STOPPING POWER" the animal should be "shocked" into ceasing the attack thereby sparing the hunter from physical injury.

Intuitively we know that a 458 bullet will have more stopping power than a 22 by virtue of its momentum and contact area.This still may not take into the account other effects of velocity.

Taylor had his "Knock Out" tables--
Is there something better??

One fellow,James Hall, has tried to quantitate this by formula definig a KINETIC PULSE THEORY
You may wish to read and draw your own conclusions--

http://www.xmission.com/~fractil/math/kp.html

Question-
Is your rifle a poorer or better stopper than you think??

--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

Edited by hoppdoc (07/04/06 05:26 AM)

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zimhunter
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54327 - 07/04/06 05:35 AM

This is like trying to measure wind. You can measure the direction, velocity, strength, consistancy, opacity, and all kind of other factors but what have you accompolished. Non-quantifiable factors enter into stopping power in my estimation. I don't know how you measure these factors such condition of stoppee's nervous system at time of impact.
Determined to kill you, wants to kill you,might like to kill you, just making an effort to kill you. This sounds silly I know but without this type of data you can NEVER make a determination. You can make all kinds of educated guesses but in the final analysis it's still a SWAG.

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DarylS
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54329 - 07/04/06 06:52 AM

In addition to zimhunter's post, animal attitude when shot makes a big difference- at rest, eating, stomach full, alert, excited, frightened etc.
: There is no mathematical formula that works perfectly or well for that matter.
: The KO, Pounds Feet(momentum) theries seem to work better than Ft. Lbs., but still don't work all the time.
: Having a relatively small, lightly framed deer absorb 3,000 pounds of anything and still run 100yards makes the FPE numbers seem ridiculous. The FPE formula means that that particular bullet should move 3,000 pounds 1 foot, yet the deer just dashed off weighting but only 120 pounds. Go figure. Slap it in the same place with a .457" 405gr. Rem or W soft point doing 1,500fps with 1,300FPE at impact and it drops - generally. Nothing seems 100% perfect.
: Animals are just that, living, breathing entities, that don't read ballistics tables.
; However - slap them right, with something big, moving at a reasonable pace, and the die quickly, generally.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

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hoppdoc
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Re: STOPPING POWER-How to best measure it?? [Re: zimhunter]
      #54331 - 07/04/06 07:17 AM

Obviously the ability to stop any animal depends on its intent to kill you, etc,etc. It also varies with the location and effects of the non-fatal CNS shot you deliver. If we continue to talk about RESULTANT stopping power we are helpless--

But somewhere in there is DG EFFECTIVE STOPPING POWER-- the objective sheer contact force applied( ability to move objects) delivered to the animal. Empirically this should be able to be quantified if the bullets total energy is expended in the object shot.

The reviewer Hall feels the answer lies in the bullet energy acting thru the bullets momentum and tries to validate this thru bullet cavity volumes et al.
bullet energy x momentum!!

My fluids mechanic engineer friend disagrees somewhat since the shot object is penetrated with a certain diameter bullet.
He suggested a empiric formula for DG stopping power might proportionally be--

bullet energy x momentum(mv) x expanded bullet cross sectional area(soft points).

This still doesn't take into effect hydrostatic shock,etc.

Sorry for all the math BS but it is always fun to try to figure out which rifle is the bigger stick--

Hope I didn't bore everyone to tears.

--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

Edited by hoppdoc (07/04/06 07:21 AM)

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allenday
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54335 - 07/04/06 08:58 AM

I measure it by:

A) Bullet placement

B) Bullet construction

Everything else is in the running for some sort of "sloppy-2nds" award.

I think most guys talk a better game than they play. I also think that doubles are VASTLY overrrated, and most guys are entirely too preoccupied with rifles that exceed their ability to really and truly shoot well...............

AD

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JPK
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Re: STOPPING POWER-How to best measure it?? [Re: allenday]
      #54343 - 07/04/06 10:10 AM

On the other hand, experience has shown that bullets of .458" or better at velocities of 2050 or better can stop an elephant charge with even pretty poorly placed shots.

Stopping an elephant with a missed frontal brain shot means either turning it knocking it down. As for turning an elephant, who knows if a 375H&H wouldn't have done the same in those circumstances with that elephant. But when it comes to knocking an elephant down, this is an arena only the big bores run in.

A hundred and six years of experience with hundreds of thousands of elephants shot by thousands of hunters is silly to ignore. If you doubt history, watch Buzz Charlton's video. Results follow history, his comments reflect history, though of course there isn't the sample in any one video or PH's experience alone.

As for choice of rifle, bolt or double, I believe that for elephant hunting the big bore double is without rival.(This assumes the fellow using it knows his rifle, of course. In Buzz's video there are two examples of fellows who don't, and Buzz makes the comment that fellows unaccustomed to their double have an issue with double triggers.)

When it comes to buff, I suspect a true charge might be harder to stop. But a true charge is also a hell of a lot less likely too seems to me. Of all the buff charges I've seen on video, if the cns was missed, the bigger the calibre the more the effect, including knocking them off their feet or hurting then so bad they slow to a crawl. Not nearly as much has been written about buff hunting than elephant hunting, or at least I haven't read it, and there isn't the clear lesson to me.

I think a double is great fun to use to shoot buff so long as you are either willing to pass up on shots or trade out for the scoped bolt (of legal calibre) your tracker ought to be carrying. If you could only choose one rifle and the trophy was more important than how you got it then I believe that a bolt with a low power scope is the rifle to use.

My thoughts,

JPK

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hoppdoc
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54348 - 07/04/06 10:58 AM

My friend Jeff, the fluids guy says his formula with the cross sectional area compensation is flawed and a no go.

Without getting exotic he thinks the formula of
energy x momentum appears good for noting the comparible effects of bullet forces on uniform tissues.

Interesting that a 375 H&H with a 300 gr pill has an index of
13,862 and a 470 NE 500gr @ 2150 has an index of 24,491!!!

The 458WM 500 gr @2050 has an index of 21,230 while the
500 NE with a 570gr @ 2250 has an index of 36480!! At 2150 fps it still has an index of 31829!!

All these calculations are great fun but one still must shoot the animal properly in the heart lung region or head(non CNS hit) with the bullets staying in the animal for it to have any merit. Past experience with Elephant shooting other than CNS shots should apply.

Does this method effectively compare the "stopping power"
of non CNS shots??

You decide!!

--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

Edited by hoppdoc (07/04/06 11:23 AM)

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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54350 - 07/04/06 12:21 PM

hoppdoc,

This is all an exercise in mental gymnastics, in my honest opinion.
Having said that, and in regard to your friends formula, several buddies of mine and myself started to compile the volumes of traumatized tissue from various calibers with recovered bullets. What we found is that there is a descent correlation between bullet velocity, frontal area, and the speed of sound in the the tissue medium. Now granted we made some rather sweeping assumptions with regard to the speed of sound in the tissue medium. The reason one must consider the speed of sound and the frontal area (and shape, but that tended to be rather consistent bullet to bullet with regard to soft points) is the hydrodynamic effect of the bullet on the tissue itself. Anyway, enough mental gymnastics.

Real world stopping power. Well I can tell you from first hand experience if you shoot a bison in the head with a 300 Win mag and miss the brain it doesn't really do anything (okay it bleeds a bit), lets call that a stopping power of 0. If you shoot a buffalo or bison in the head with a 500 Jeffery and miss the brain they typically fall down, and take a few seconds (only one I had this happen to that didn't die took about 20 seconds to get back up) and it wasn't feelin' too good when it did ie no more walking, running, let alone chargin'. I have actually killed a few with missed brain shots (two to date) both expired from broken necks, believe it or not, again shot with a 500 Jeffery improved. The 416 and 375 I have seen only two from the former and one from the latter and neither was able to drop a buffalo or really impress them too aweful much with a missed brain shot. By the way, brain shots ain't as easy to make as many seem to think!

Buffalo can run a good many yards with absolutely NO heart (something in the area of 30 to 50 yards for sure I have seen it myself). The 500 Jeffery Improved with a 570 gr Woodleigh at ~ 2400 fps will literally explode the heart, and leave a wound channel of ~ 6" to7" in diameter with an exit hole around 3" to 4" (rib cage now not hide). The buffalo can still run far enough to stomp your arse. By the way, in my experience buffalo typically won't consider charging unless you are inside ~ 30 yards. The closer you get to them the higher the liklihood of a charge. At these ranges they can easily get to you even with a shattered heart and a shattered front leg.

The truth simply is the only RELIABLE charge stopper is a CNS hit. The real big bores (500 and up) do seem to provide some margin for error in that they will knock down an animal with near brain misses (and in my actual experience can actually kill). The lesser calibers do not seem to provide this little extra insurance.

That is all I have to say about that.

Scott

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zimhunter
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54351 - 07/04/06 12:25 PM

In the final analysis if he doesn't stop when you shoot him it wasn't enough. QED

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luv2safari
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54353 - 07/04/06 12:55 PM

Stand in front of the gun, instead of behind it...thats the acid test.

--------------------
Hunt with Class and Classics

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hoppdoc
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Re: STOPPING POWER-How to best measure it?? [Re: zimhunter]
      #54365 - 07/04/06 08:29 PM

My hunting buddy Bob is very amused at all this--

He said,
"Big bullet, Big hole, Little bullet Little hole, so carry and shoot the one for the biggest hole you need!!"

Can't say I can disagree with that logic!





--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

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hoppdoc
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54439 - 08/04/06 10:48 PM

Further confusing testing offered to hunters--
http://www.handloads.com/misc/linebaugh.penetration.tests.asp

I was surfing the net on 470 NE issues and came up with the Linebaugh penetration tests and related articles.These seem particularly misleading in suggesting to all hunters that handguns/less potent firearms can be effective hunting tools on the basis of penetration. It suggests that a 500 Linebaugh pistol,450gr@1300fps is better than a 470NE 500gr@2150. They used bone backed up by wet paper and noted penetration. Wet paper testing is not reproducible in my limited look at penetration testing media.Solids vs softs testing isn't valid in this media either.
It was comforting to note the 600 Nitro blew up the whole test apparatus.

I think many people get misled by penetration=stopping power.Yes a 7x 57 will head shoot,penetrate and kill an Ele but will it stop a charging Ele with a non fatal CNS hit?

I feel it is the proper combination of penetration and applied energy dump into the dangerous game animal to harvest/survive it.The kinetic pulse theory gives the "whack" info and past experience gives bullet type,SD/velocity needed for the penetration to reach the vitals on the toughest hunting shot angles. I personally think you need BOTH unless you never screw up your game shots a bit.

Judgements based solely on artificial medium testing can get you KILLED!! Prior hunting of the beasts is the real/ultimate crucible to see if a particlar firearm makes the grade!!

--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

Edited by hoppdoc (08/04/06 11:55 PM)

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MRobinson
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54544 - 10/04/06 12:38 PM

If you are alive when the shooting is over, your rifle had enough.

--------------------
Mike

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Will
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #54598 - 11/04/06 06:24 PM

Taylor's KO values are probably as good as anything around, which indicates the effect of a near miss.

You need the combination of sufficient bullet energy and penetration, to have the potential for "stopping." As Zimhunter stated, part of it is attitude of the enimal but only a charging animal needs stopping.

What works one day may not work the next, which is one reason for a backup hunter, whether a PH or someone else.

The 4000 ft-bs and 400 grs. is a courtesy to the 404 Jeffery and 450/400 crowds. It is not much of a stopper except in experienced hands. But then nothing is really a stopper unless used by an experienced hand, or turns out to be a lucky shot!

--------------------
_________________________________________________
Bill Stewart

Once you have been amongst them, there is no such thing as too much gun.

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bulldog563
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Re: STOPPING POWER-How to best measure it?? [Re: Will]
      #54722 - 13/04/06 06:19 PM

Gregor Woods came up with his own version of the TKO called Relative Damage Potential (RDP). I haven't studied it very much but Richard Harland feels they are an improvement over TKO values. Those who are interested a description is located on pgs 167-169 or "Ndlovu" by Harland as well as in Gregor Woods' book "Rifles for Africa."

Just a few examples of RDP #'s

700 NE= 110.0
577 NE= 59.1
500Jeff= 35.9
458 WM= 23.9
375 H&H= 11.9

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jro45
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Re: STOPPING POWER-How to best measure it?? [Re: hoppdoc]
      #56562 - 07/05/06 06:34 AM

I think using foot pounds for each caliber. Like the 416. Mine has over 5000 ft pds at the muzzel.
It doesn't have to be this high for different game tho.

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ALF
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Re: STOPPING POWER-How to best measure it?? [Re: jro45]
      #56570 - 07/05/06 09:16 AM

Allen day has the correct answer

There is no approximated mathematical number or eqation that has the ability of measuring wounding effect of a projectile.

What we can do is to model and predict how a projectile behaves in the target, what we cannot do however is to predict how that behaviour would effect the animal or person you are shooting.

The various stopping and knock down formulae are just formulae and do not in any way represent wounding capability as none of them take projectile path and target physiological and psychological reserve into account.

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SAFARIKID
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Re: STOPPING POWER-How to best measure it?? [Re: ALF]
      #56576 - 07/05/06 01:14 PM

Here is a neat TKO Chart and it is simple to plug in your info/specs...
http://matrix.dumpshock.com/raygun/downloads/taylor.html

I LIKE TKO,but also agree with several above replys and of course,luck and bullet placement have quite a effect...Last,bigger holes are a good indicator!

--------------------
Lots of BIG Bores!

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hoppdoc
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Re: STOPPING POWER-How to best measure it?? [Re: ALF]
      #56611 - 08/05/06 09:06 AM

We can all discuss stopping power and most will agree that it is a relative quantity that increases with the size and velocity of projectiles.

If we talk real world we all know that nothing is guaranteed and that an attacking or adrenalized animal makes all this inductive calculation irrevelant.

Then as one poster puts in his post signature, your options have become wonderfully simplified--either you kill/stop the attacking beast or someone will be writing your epitaph!!

I would certainly hope that mine would never be-"Couldn't hit the stopper and didn't use enough gun!!"

--------------------
An armed man is a citizen of his country, an unarmed man just a subject.

Edited by hoppdoc (08/05/06 09:07 AM)

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