Here´s a link to an interesting article I found today.

Bullet Spin Contribute to Bullet Failure?

It did got me thinking.

Your opinions ??

Cheers,


Nsiro

Okay, my opinion: A little bit of knowledge is a dangerous thing. Apples aren't like oranges. The author is using fuzzy logic and worse.'

There is no point is using a twist rate faster than required to stabilize the bullet you're using, on that point I agree with the article. There are adjustment factors for the Greenhill formula, to be applied according to velocity.

Bullet RPM is far more influenced by twist rate than velocity, the latter near the ragged edge of insignificance. The energy level attributable to twist(rpm) is likewise insignificant. Velocities in the range discussed in the article are well below the threshold that generates structual breakup in flight...the anaolgy superfluous.

I would not be too quick to attribute bullet failure to fast twists however. I note that many guns work effectively with relatively fast twists, the 7x57 Mauser first to comes to mind. Methinks bullet construction far more significant. For all of that, if you don't want a 12" twist in your .375, don't buy it.

JMO

The author's analysis rings false to me. The author is saying that breakup occurs within the target because the stress of centrifugal force coincides with the stress of impact. In fact all parameters change dramatically at impact. The bullet slows, if it is softpoint it changes shape, as it changes shape it compresses, and if it does not mushroom and is a spire point it tumbles end to end. Any of those dynamic changes would dramatically change rotation.

Either the author is referring to extremely frangible bullets in unusual circumstances, or somebody is misusing bullets. One example of the former has been reported by .220 Swift shooters, with the high velocity or that rifle causing bullet disintegration in flight if inappropriate projectiles are used. That is an old issue with no need to re-invent the wheel.

My take is he is discovering that extremely frangible bullets sometimes disintegrate within targets. That may infer that the bullet he is using is right on the edge or beyond of what is appropriate for that bullet in terms of speed and target. What it more probably suggests is that his editor was pressing at the last minute for an article and the editor, not being a shooter, can't tell the differance between sh!t and shinola.

Reader Beware: Chris Bekker is a poseur and not competent to address technical matters in ballistics. He misuses valid scientific terminology to lend credence to his spurious theories. Force and energy are not the same, but Bekker doesn't know how either applies to the mechanics of bullets in flight or in penetration. He also seems unaware of the principle of conservation of energy. How can a .375 H&H bullet have 90,000 ft-lbs of energy? There isn't that much energy contained in the propellant that launched it. Bekker's calculations are invalid in terms of essential mechanical principle, in formulation and in resulting units. Moreover, his arguments are invariably of two stripes: 1) hypothetical cases drawn from these invalid calculations, or 2) hearsay. I defy anyone to find evidence of hard data in any of Bekker's writings. So, let me provide the oft-quoted disclaimer: "For entertainment purposes only".

Actual experiments show that internal stresses on bullets due to angular velocity (properly expressed as radians/second) only causes problems in terms of disintegration when the bullet is very small and also absorbs a lot of heat from friction in the bore or has an extremely thin jacket (think varmint bullets). In either case material failure can result in spontaneous disintegration in air.

Angular velocity does have a beneficial (but very slight) effect on hunting bullets in terms of promoting expansion and (to a greater degree) in keeping solids point forward. I have never seen any evidence of a detrimental effect on any conventional bullet across the range of typical velocities (less than 3500 fps). Bekker's entire premise is predicated on the unsubstantiated claim that the .375 H&H is unreliable due to a fast twist rate and/or high velocity. Examine that claim and you will doubtless agree that it is immediately suspect.

also as velocity drops off as does the spin and some point the bullet goes to sleep.
Did i miss something.
Wops for got to say, dont we match our bullets to the game and velosity they were intended for.

Ulfhere,

Care to post your real name and contact details here? I am an amateur and a learner, no expert at all, but if you would like to contradict someone it would help if you had the honesty to post your credentials and contact details.

Your not doing that does not even impart entertainment value to your post.

Mehulkamdar, I don't know Bekker from sunrise but the lack of posted credentials by ulfhere does not invalidate the truth.

Few people here are anything but professional in regard to ballistics, we aren't lucky enough to get paid for studying our hobby. That does not preclude learning fortunately.

I do not know if this site addresses the issue but there is a boat load of information on terminal ballistics on it, the author a PROFESSIONAL ballistician:
http://www.rathcoombe.net/sci-tech/ballistics/wounding.html
If you wish to question the matter I believe there is a contact address. The fella knows his stuff...

DigitalDan,

I have clearly said that I do not know enough about ballistics to comment on this topic. Several other members have posted contradictory views here and I am sure all of them know more than I do. I have no argument with people who know more than I do on a particular subject and I have not addressed anyone else's comments.

Ulfhere registered today and has attacked another member here calling him a poseur and some more. That is why I asked him to post his real name and credentials. I am sure there could be discussions that take place openly and without someone hiding behind a false name to piss on someone else because of some personal grievance.

Best wishes and good hunting!

Mehul, I have not posted my name in cyberspace for three reasons.

The first is that the truth does not depend on personality. I encourage the scientific approach to new information: doubt it, research it, test it. Don't depend on the credentials of the one promoting it. Many bad mistakes have been made that way. Everyone makes errors. I invite everyone to question everything that I have stated. Do your own investigation. Draw your own judgment on the facts. But let the facts be the matter at hand, not a curriculum vitae.

The second reason is that I do not seek self promotion. I do not want to be a famous name in shooting circles.

The third is that there are crazy people in cyberspace, including on this forum. More than once some kook has threatened to kill me for disagreeing with his extreme views and I see no point in making that task any easier for them.

What I wrote was harsh, I freely admit. But I would have thought that the readily offered evidence of the 90,000 ft-lbs would have settled any doubts. I have tangled with Bekker and his publisher in the past over his bogus theories, misappropriation (and misrepresentation) of my material for the purpose of making himself look like an expert (read there: plagiarism) and distortions of things I have said when I challenged them regarding their conduct.

I do not severely criticize anyone for an honest mistake or simple ignorance. But for those who willfully engage in imposture and unabashedly publish material that is wrong, I reserve no mercy. I attempted to admonish Bekker years ago in private when I learned of his misrepresentation of my data in his dispute with a bullet manufacturer in South Africa and he became publicly vindictive. That is the difference between one who wants to learn and to be correct in their knowledge, and one who merely wants to be thought an expert.

Although this user ID is a new one, I am an old member as any number of old members can attest. If you want a character reference, I suggest you ask them.

Not to mince words this article is complete Bullshit. The author uses completely ridiculous logic unfounded by any scientific principles. The following quote will illustrate this:

[quote]
As it is extremely difficult to isolate the effect of bullet spin on bullet performance, I have opted for the concept of “Total Force†- being the "Forward Force" multiplied by the "Rotational Force" - to try and address the forces that would break up a bullet, fragment, or cause it to lose weight.
[unquote]

The total energy of a bullet consists of the amount of energy created by the combustion of the rifle powder. This energy is then expended in several different ways. Heat, barrel friction, inertia etc. all consume parts of this energy. The total energy when the bullet leaves the muzzle is of course a function of the Mass and the velocity. The energy contained in the rotation of the bullet usually works out to be about 4/10ths of 1 percent of the total kinetic energy. If you want to research the actual equations check out "Understanding Firearms Ballistic" by Robert A. Rinker.

You simply can't make up scientific equations like "Total force = forward force multiplied by rotational force" ! Doing so is complete unscientific jibberish that completly falsifies any conclusions made with such bogus assumptions. Deal with scientific facts and not "equations" that this author "opt for the concept" or makes up..............DJ

mehul,

Ulfhere is, in my opinion, the foremost expert on terminal ballistics. In fact I invited him to comment on my topic on "large humane wounds".

A friend who is one of the top manufacturing engineers around read Ulf's work and commented "He knows as much about the topic as anyone that I know of and has put in writing better than anyone".

quote:

---

Originally posted by Ulfhere (HTL):
Reader Beware: Chris Bekker is a poseur and not competent to address technical matters in ballistics. He misuses valid scientific terminology to lend credence to his spurious theories. Force and energy are not the same, but Bekker doesn't know how either applies to the mechanics of bullets in flight or in penetration. He also seems unaware of the principle of conservation of energy. How can a .375 H&H bullet have 90,000 ft-lbs of energy? There isn't that much energy contained in the propellant that launched it. Bekker's calculations are invalid in terms of essential mechanical principle, in formulation and in resulting units. Moreover, his arguments are invariably of two stripes: 1) hypothetical cases drawn from these invalid calculations, or 2) hearsay. I defy anyone to find evidence of hard data in any of Bekker's writings. So, let me provide the oft-quoted disclaimer: "For entertainment purposes only".

Actual experiments show that internal stresses on bullets due to angular velocity (properly expressed as radians/second) only causes problems in terms of disintegration when the bullet is very small and also absorbs a lot of heat from friction in the bore or has an extremely thin jacket (think varmint bullets). In either case material failure can result in spontaneous disintegration in air.

Angular velocity does have a beneficial (but very slight) effect on hunting bullets in terms of promoting expansion and (to a greater degree) in keeping solids point forward. I have never seen any evidence of a detrimental effect on any conventional bullet across the range of typical velocities (less than 3500 fps). Bekker's entire premise is predicated on the unsubstantiated claim that the .375 H&H is unreliable due to a fast twist rate and/or high velocity. Examine that claim and you will doubtless agree that it is immediately suspect.

---

ULFhere is absolutely correct. If you will take the time to read any more of Bekkers Psuedo-Scientific Baloney you can see that he pretty makes up equations to prove whatever pre-conceived notion he has. I find it amazing that he spent enough time to write as much different falacious crap as he did on his website. I've never met him, seen his stuff before and have no previous bones to pick with Bekker other than the stuff he is trying to pass off as scientific analysis is a bunch of made up Excrement.............DJ

quote:

---

Originally posted by Ulfhere (HTL):
I have tangled with Bekker and his publisher in the past over his bogus theories, misappropriation (and misrepresentation) of my material for the purpose of making himself look like an expert (read there: plagiarism) and distortions of things I have said when I challenged them regarding their conduct.

I do not severely criticize anyone for an honest mistake or simple ignorance. But for those who willfully engage in imposture and unabashedly publish material that is wrong, I reserve no mercy. I attempted to admonish Bekker years ago in private when I learned of his misrepresentation of my data in his dispute with a bullet manufacturer in South Africa and he became publicly vindictive. That is the difference between one who wants to learn and to be correct in their knowledge, and one who merely wants to be thought an expert.

Although this user ID is a new one, I am an old member as any number of old members can attest. If you want a character reference, I suggest you ask them.

---

So, you must be the opponent to Mr Bekker from the long debate that took place in Sporting Rifles. Mr Ledbetter, I presume?

Cheers
/ JOHAN

Johan, you usually seem to be quite sensible. Do you find Mr. Bekkers work as ridiculous as do we?............DJ

In my college days long, long ago, I was subjected to a comprehensive two semester course in physics. The two things that I learned about physics and probably the only things that I would want to defend is that 1) you may be good in math, and you may be good in science, but that does not make you a good physicist. Physicists (the real guys) are wired differently than the rest of us, and 2) as soon as you assume something in physics, or begin to rely on intuition, you have one foot over the end of the gang plank on which you stand, and the sharks are looking up with grins on their faces!

One thing that has not been mentioned in these discussions that puts the whole premise posed by Mr. Bekker into question is the matter of conservation of angular momentum. What this principle states is that a rotating body will conserve the energy of rotation – if the diameter of the body is increased, the speed of rotation will decrease accordingly. This means that as a bullet begins to expand, the speed of rotation is reduced proportionally. The everyday example of this physical law is an ice skater spinning on the ice. If the skater extends their arms, the rotation slows to a crawl – as the skaters arms are drawn in tight to the body, the speed of rotation is increased to a blur. An expanding (expanded) bullet does not have the same rotational velocity as an unexpanded bullet.

Learned Gentlemen
A question for those that are far more knowledgable then I. Does the depth of the rifling play a part in the frangiblity of the bullet? Or put another way does rifling prestress the bullet promoting failure?
Assuming that two identical bullets, 375, 300 grain are moving at 2,000 fps impacting the rump of a bull moose at 100 yards, one rotating from rifling 1/12 and the other not rotating at all. Would both bullets react the same?
Jim

I'd say no, rifling depth does not affect frangibility, assuming reasonable limits. There are a lot of variables in that department. Yes, land engraving causes stress on the bullet, but...mebbe more important is construction design and materials, twist rate and velocity, and on and on and on and on.....JMO

As to the second, first problem you're gonna have is hitting a bull moose in the butt with a 0:0 twist. Long odds against equal performance when one hits sideways... Natural Fact

I'm not all that learned, whatever that means.

Dan
It's crossed my mind, believe me it's a short trip, if a bullet had driving bands, like artillry, that actually engaged the rifling rather then the projectile itself, would the bullet integrity be effected?
Jim

.

Arky, I think that driving bands would actually reduce that influence. In arty rounds the case is steel, the driving bands a sofer alloy of copper or some such. The DB material will flow under engraving stress, the "hull" will not.

In the TSX I speculate that the grooves actually act as stress relievers in that they provide space for metal displacement. In conventional bullet scenarios the bullets are actually swaged in the process of land engagement, lands on opposite sides squeezing jacket and core(both ductile) to fit. Given that bullets and groove diameter are likely to be similar, any resulting deformation(very small) may propagate along the longitudinal axis of the bullet. This is one reason for the ongoing interest in odd number grooves amongst accuracy nuts, theory being that the bullets are not stressed as much in the engraving process since lands and grooves are opposite each other, given equal widths. I see nothing wrong with the theory but can offer no references to support same.

Minutae: Some barrels have radiused surfaces betwixt land and groove on the driving side and are known as "R", ie 5R or 7R rifling. Again, this in an effort to reduce deformation. Apparently there is some substance to this as well.

Given a "perfect" metal surface w/o flaws or deficiencies in alloy, ANYTHING than impinges on same, or penetrates the surface induces STRESS MULTIPLIERS. I don't recall the precise factors, but a hole may be a "3", a scratch mebbe a "6", a fracture, well, off the scale? It relates to your original queston about frangibility but I cannot pontificate on the specifics of the issue. Hope this didn't muddy the waters too much. Rest assured that others will spash some chlorine in my pool if I've been feeding you BS on this.

I guess I'm just getting old. It seems like every few weeks some new troglodite has an epiphany that envisions rotational forces having a profound effect on terminal ballistics (bullet expansion).

Okay, let's assume the trogs are right. "For every action there is an equal and opposite reaction." Simple, but genarally accurate. So, the forward energy of the bullet is reflected in the recoil of the gun. Likewise, the rotational energy of the bullet is reflected in a counter-rotational torquing of the gun around the axis of the barrel.

So, how many of you have had the gun twisted out of your hands by the immense rotational energy it has imparted to the bullet? I thought so. The rotational energy is so minimal, even with a "fast twist" barrel, as to be de minimus in its effect on the bullet's terminal behavior.

Wish I could contribute here.....Try as I might I couldn't follow the logic in the article.....I realize that somethings are complicated.....and I'm rather capable of following some amount of complication being a degreed engineer.....I just couldn't follow this article.

I won't conclude that it's pure BS....but in my mind if I can't comprehend the logic....it is as far as my interest goes. Things unraveled fast when we multiplied foreward momentum by rotational force.....WTF is that?

Vapodog, you've got the right idea. Let me simplify it. Bekkers statement " I have opted for the concept of “Total Force†- being the "Forward Force" multiplied by the "Rotational Force" ", is completely fictional crap. When you base your conclusions on completely fictional crap your conclusions are also completely fictional crap........DJ

Uh, Vapo...mebbe it's that new math, or perhaps something like the military concept of "force multipliers", as in Aerial Tankers, JSTARS, etc. etc. Some of it's voodoo, some of it the real McCoy. On the internet we get to decide which.
As to whether it was pure or not, I will not pass judgement, but it has a decided aroma...

Arky, in regards your question, Harold Vaughn touches on the issue in the context of my discussion in his book, Rifle Accuracy Facts. Good read in any case, from a genuine rocket scientist who can speak english. Available via Amazon.com

I just received this e-mail from Mr Chris Bekker and am cutting and pasting it here. He has not been able to log in and I am posting on his behalf.

Harold Ledbetter wrote:

"Actual experiments show that internal stresses on bullets due to angular velocity (properly expressed as radians/second) only causes problems in terms of disintegration when the bullet is very small and also absorbs a lot of heat from friction in the bore or has an extremely thin jacket (think varmint bullets). In either case material failure can result in spontaneous disintegration in air."



--------------------------------------------------------------------------------


The Challenge:

Bekker's says himself that his theory, that excessive spin contributes to bullet failure, needs further laboratory analysis to be conclusive as it is not scientific, but merely a method applied across the board to see comparative differences. Harold Ledbetter insists that only pure science be used and now claims that such experiments have been done. That sounds great, but bring on the scientific evidence. Under who's professional auspices were these tests carried out? The above explanation is too bland and wishy-washy! State the parameters, the variability of test data and the analysis thereof and how forward velocity was eliminated from the equation. I would like to see a definition of when a bullet is considered "small" and when we cross the point when the bullet is just a "tiny bit bigger than small". A critical distinction is needed between internal forces and those shear forces on the surface of the expanding bullet and the contribution of each to bullet fragmentation. Then on the heat issue it would be interesting to asses the role of heat and the degree to which it contributes to bullet failure - at which point (temperature) can the bullet sustain the heat and this should be related to different wall thicknesses, as the inference is that it only happens to extremely thin jackets. What is extremely thin? Only varmint bullets? Bullets with a thickness of 0.45 mm (conventional bullet), or less or somewhat more or does this phenomenon happen in sympathy with more powder behind the bullet that propels it faster and hence generate more heat. We need to know the different bullets and cartridges that were used as well as velocity variations to push the experiment to its limits, as well as the variation band of the twist rates that induced the rotational velocity. Also state the metallurgical analysis of the gilding metal in question. The methodology must be explained, software used and mathematical techniques employed to get a handle on the situation.

Spontaneous disintegration in air is not the issue - it never was. The issue under discussion is terminal disintegration when the bullet meets the resistance of flesh. Bring in a co-efficient of retardation for flesh as well. We need to see it in a test medium such as ballistic gelatin or some other medium considered appropriate. Once that has been established we need another co-efficient to relate it to animals to be empirically correct. If this research report is not published in the next 48 hours, and it does not prove the matter conclusively, then my submission would be that it does not exist and amounts to no more than speculative conjecture. Bring the hard evidence that you expect from others, buddy. You are now being judged the way we expect from a scientist and I promise you the scrutiny of a friend that has a PhD in physics. I don't want to prejudge the situation, but I have a feeling in my stomach that the tests you referred to is not going to stand scientific scrutiny and may well be just as unscientific as Bekker's theory - with one difference, Bekker stated categorically that his theory was not science.

Good hunting!

Mehul, What a crock of S***. He comes up with a verbose demand for rigorous scientific proof with a 48hr time limit when he himself admittedly is not scientific in his analysis and makes up equations.
If he can E-Mail you he should be able to log on. I'm sure he doesn't because it isn't at all hard to show that his stuff is complete baloney..........DJ

Is this guy related to John Kerry?

DIDN'T READ the article,
BUT
passing on a twist rate experience.
When they first came out with the 1 in 7 twist rates for the new AR15s there was info included that they were designed for the heavier bullets.

So immediately a bunch of us tried to figure out what they were talking about and started running some of the lighter bullets we could find.

What we discovered was that about 10% of the time the ultralights were coming apart before they even got 100yds. They shot fine through the 1 in 9s but in the 1 in 7s they were for lack of better explanation, spinning themselves apart.

interesting to watch, if you looked carefully and the light was right, you could see a sort of poof where the debris blew apart.

Mehul,

If someone demanded of you that you prove, using rigorous scientific methodology, that there was NOT a strong correlation between tidal forces and yeast infections in menstruating women because the moon was made of cheese, where would you begin?

It isn't necessary to accept yours or Bekker's challenge (I can't tell who wrote what) that I prove why an absurdity isn't true. In the first place proving a negative is, as you should know, rather hard to do. That would imply that you have considered ALL possibilities, which isn't likely or, in any event, proveable. In the second place, Bekker's methods are demonstrably wrong. I gave one example. Anyone passingly familiar with mechanics could find others in a matter of minutes. But the most important reason why this is unnecessary is that <I>there is no evidence to indicate that this alleged phenomenon even exists</I>, or at any rate Bekker has not provided any. So asking me to provide all of this is a bit like asking me to disprove the existence of the Easter Bunny. No thank you. Anyone with the proclivity to accept such a premise is more than welcome.

Now, if you want to see some evidence to the contrary, take a look at Gary Sciuchetti's study of terminal performance of 180 gr .308 caliber bullets published in Handloader magazine ("The Best Hunting Bullet", June 1998, No 193, pp. 40 - 44). In that article, in order to avert critcism of his test method, he examines the question of imparted angular velocity. His concern was that someone would (rightly) ask the question how did he know that he was getting a realistic result of a bullet as if it had slowed in air (his tests were done using reduced loads to get lower velocities in some cases). Angular velocity is not diminished in flight or in penetration to nearly the degree that axial velocity is lost. He conducted a series of tests showing impacts in his wetpack test medium (which he correlated separately to several different shotlines through deer cadavers) that compared impacts of the same velocity, but with some bullets launched at close range using reduced loads (lower angular velocity) and others at long range (naturally slowed, higher angular velocity). His conclusion was that there was no difference. I would qualify that to say that the difference was slight. I would further contend that the differences are largely captured by the combination of conditions: differeing twist rates in rifles, different cartridges having varying muzzle velocity, as well as different ranges. All of which work fine.

Nothing in his testing revealed any hint of a risk of failure, nor have I ever seen or read or heard of any such problem. Again, anytime someone begins an argument with the claim that one of the most highly regarded cartridges of the last century is intrinsically unreliable you have to ask yourself whether his sources can be very good.

The only evidence of which I am aware of anything remotely akin to this question comes from varmint and smallbore wildcat cranks who drive .224 bullets with very thin jackets to velocities in excess of 4000 fps. It is widely documented by such shooters that in some such instances the bullets visibly explode in the air or else never arrive at the target. The reason would be that the combination of a thin jacket (providing little mechanical strength and possibly pre-stressed by the rifling), a lead core approaching its melt temperature due to friction and gas heating (or aerodynamic heating according to some, though I doubt this) and the influence of the angular acceleration causes the bullet to peel apart and disintegrate. Even here, the significance of the twist rate is not clearly dominant. Undeniably, the thermal load is the driver.

We see a similar effect in soft copper shaped charge jets, which incidentally spin at much higher velocities and yet somehow seem to penetrate monolithic steel with no difficulty - unless they get hot enough for the core to melt and then they fly apart. In my view temperature is the key element, not angular velocity.

If that does not satify you, I am sorry. But I will not waste my time on foolishness, nor lend credence to crackpot theories by engaging in an investigation of unsubstantiated nonsense.

quote:

---

Originally posted by Ulfhere (HTL):
Mehul,

It isn't necessary to accept yours or Bekker's challenge (I can't tell who wrote what)

---

Ulfhere,

I have been clear that this was posted by me on Mr Bekker's behalf. My e-mail ID is in my profile and I communicate with several members here as well as on other forums. When I receive a request, I try to help if I can and I do not have any problem with doing that for any member as quite a few have helped me with advice, books and tips on more than a few occasions.

I do not know about ballistics at all and have only one rifle in the US with which I hunt. In India I hunted with a 12 bore shotgun most of the time. I think I have made this amply clear in the one year plus that I have been a member here, something that you would definitely know had you been coming here for that long as you say you have been doing.

I received Mr Bekker's e-mail and posted his note here - I said as much on my post. Whether you reply to it or you don't is your previlege.

And don't worry about apologising about "satisfying" me. I have said that I am a learner and I am grateful to anyone who has anything to teach me and others who are, presumably, also learners like me. If you find that offensive, I shall not read your posts if it bothers you all that much.

I received the following mail from Mr Bekker - Ulfhere, please note that this is not MY post but Mr Bekker's:



Harold Ledbetter (Alias HTL),

I am compelled to reject the one-sided misconstrued personal attacks you posted on me. Don't blame the editor of Sporting Rifles for not getting your way, as he must have seen your ill-intent. With your recent comments about me, I should be motivated now to criticize you on your unscientific publications in a relentless way - just to return you the favour. I had 4 attempts to get you to follow what I had written and despite me telling you that it was a simplistic guide, you insisted to evaluate it on a scientific way. I grant you that, but then I will apply the same rules to you. I kept all the personal correspondence between yourself and myself. Just one other thing ... Harold, you will not say all those rude things to my face as my male hormones won't allow that, but the luxury of distance affords you that protection. However, to redeem myself in a small way, I would like to share with the readers my last letter (30 Sept 2002, 1:55 pm) to yourself and hopefully they can gain a better insight on how twisting and willfully deceitful you are - slyer than a snake! I don't need your "scientific" dribble on bullets and wounds on game. My practical experience on game (empirical results) is worth far more than your paper wounds. You can dance around other people with your double talk, but not me.

You still did not give me the hard evidence - mostly hearsay Boet. I need to see the hard scientific evidence (must be conclusive) published. To me it is still a generalized and inconclusive explanation of the effect of twist on frangible bullets. AS SCIENTISTS we cannot leave any room for opinions and apparent logic. Let me remind you of the essence of the issue - excessive spin combined with inbuilt design weaknesses by virtue of thin-jacketed conventional bullets, where for example the .375 bullet has an equally thin jacket than a .284 bullet with a drastic difference in the kinetic energy that these two bullets carry. You can reject this if you will and you can blame all sorts of other factors. I don't underestimate the complexity of the project and therefore won't begrudge you if you leave your scientific inheritance for the next generation, including your terminal model based on your confusing and unscientific paper shooting results that current PC's cannot run in a day. In your proposed model, I am sure you would also discard the role of sectional density (SD) based on your skewed tests that you regard as science (that's why you published it, right - only "science", remember). I think hunters need practical guidelines that work, more so than unpublished science or science in the making that are so complex that it would even stun Abraham Lincoln, if we could bring him back.

"IF IT IS NOT SCIENCE, IT SHOULD ALL BE FOR FUN & ENTERTAINMENT"


--------------------------------------------------------------------------------

Speaking with forked tongue - HTL

In HTL's vengeful showdown of my KOV theory that does not work according to him, gave me the opportunity to look deeper into his paper shooting and because I dared to criticize his unscientific and confusing wet paper shooting at point blank range, and me pointing out the mistakes he made trying to interpret my model, he now reverts to double talk with a dexterity of words. So, I just wish to illustrate with some examples how any potential reader is taken around the mulberry bush to a drunken state, where he is left so confused as to what was really said or what to believe. He calls my work a concoction of formulas with apparently no value whatsoever and I say a real scientist should be more careful to base his opinions just on wet paper, especially if the results are as confusing as I pointed out .... so the readers can decide if HTL's 'science' will do them any good.

Example 1:

HTL:
"I have had my horizons expanded as far as monolithic bullets are concerned by my own experience and look forward to using them" You said this in defense of GS on his site.

Now you write: ... "I have always been a strong advocate of bonded core bullets. I am willing to be convinced that high speed monolithics can be as good, maybe better, but I want to see it demonstrated.

CB:
Your first statement leaves the impression that you have now graduated to a higher level. Then in your second statement you say the opposite ... the subtle difference being that in the first statement you lean on "my own experience" and in the second statement that "I am willing to be convinced" In my first reply I reminded you that you referred to the lethality of Bear Claws and Swift A-Frames vis-a-vis other bullets and I share this opinion, but when cornered you jumped around and came to Gerard Schultz rescue as you considered him a friend.

Example 2:

CB:
"Also note that Harold Ledbetter came to the same conclusion ..."Perhaps the most striking observation from this penetration data is that increasing velocity has a detrimental effect on nearly all bullets over the entire velocity range of interest."

HTL:
What he very carefully (again!) fails to convey is the truth. I'll quote the entire paragraph: Perhaps the most striking observation from this penetration data is that increasing velocity has a detrimental effect on nearly all [emphasis added] bullets over the entire velocity range of interest. This result surprised me because, while I knew from anecdotal evidence that very high velocities caused even heavy jacketed bullets to fragment on impact, I expected that this falloff in penetration performance would only occur at velocities above 2800 fps and, that for any given design, there would be a peak in the curve, with diminishing penetration following diminishing velocity. In fact, what is observed is that penetration reaches a limiting value rather quickly (a couple of extremely hard designs have a step function behavior) and tends to deteriorate steadily at all higher velocities. The very best performers are those (e.g., the Barnes X-Bullet and Nosler Partition) which exhibit essentially constant penetration over the entire range of interest. [End Quote]

So, in actuality what I said was that the monolithic design (and the Nosler Partition, which he also dismisses) demonstrated the most consistent penetration performance. The bonded core Swift A-Frame in fact shows a diminishing penetration with increasing velocity in the data, contrary to the allegation of Bekker.


CB:
Unbelievable ... but true ... his dexterity with words! A long explanation to bolster a weak argument. I did also quote a practical example which he completely ignores ... it simply does not suit his argument, you see. Let me quote Dr Ed Ashby again ... 'Maximizing Monolithic Bullet Performance' ... that appeared in Man Magnum of June 2000 ... "The penetration disparity between high impact velocity and low impact velocity persists with the 30.06 Spr. At 2,792 fps the 165 gr Barnes-X bullet penetrates far less deeply than it does at a velocity of 2,484 fps. At the higher velocity it frequently failed to penetrate even big chest shot warthogs completely. Thus far, there have been no failures to exit any animal shot at the lower velocity. Again, these tests involved a significant number of shots at each velocity level." This is very clear my friend.

HTL says the monolithic design has the 'most consistent penetration performance ... that is so due to its stronger design relative to soft nose bullets - we all know that, but that is not the point. The point is higher velocity will decrease penetration as Dr Asby's experience bear out - and that is exactly what I am saying as well. This will be even more true for the Nosler Partition bullet that sheds weight, up to 50% at high velocity, as the decreased momentum will cause shallower penetration on larger antelope. Now HTL believes that he has refuted what I said and I failed to explain it properly. Amazing! HTL says one thing, but then wants to explain it otherwise with a kink ... just read the initial quote again ... its is perfectly clear and I agree 100% with it. Did I mis quote him? No, I do not think so.

Then HTL throws the confusing sentence (voodoo) for the reader ... check this ... "The bonded core Swift A-Frame in fact shows a diminishing penetration with increasing velocity in the data, contrary to the allegation of Bekker." My goodness! This is not contrary to what I say .... I am not a high velocity man, everyone knows that by now, as I believe high velocity is destructive of soft nosed bullets which will inhibit deeper penetration. You are twisting my words by your own volition. Remember I proposed an impact velocity of around 2,100 fps for optimal performance ... not so? I talk straight ... not like you that loose the readers in long and incoherent explanations. My experience is that most soft nose bullets perform at their best between 2,100 and 2,200 fps save for the stronger monolithic designs such as Winchester Fail Safe and Barnes-X. That trade-off position where the bullet did not under expand due to too low a velocity and not over expand or shatter due to too high a velocity ... the performance band that I am talking about ... there is no doubt in my mind about it and this graph basically tells the same story.

Example 3:

Now this example really takes the cake ... this one deserves a medal for the art of denial.

HTL:
"I am certainly not a "speed freak" and 3050 fps is less than even a .270 Win. As I said before that rifle will do at least 3200 fps with those bullets, but I load for accuracy, not velocity. You also assert that my testing is usually in the 2700 fps to 3100 fps range. In fact almost all of my testing is done below 2700 fps and I try to get velocities that represent typical impact conditions (though of course that depends on the cartridge and the range). No one who actually reads my site will ever come away thinking that I am an advocate of the high velocity KE school of thought or that I think velocity is a good substitute for a controlled expansion bullet."

CB:
Is this not amazing? Well, HTL claims not to be 'speed freak' at 3,050 fps ... gosh! Can you see my point how this man reasons ... he shoots at a hyper fast velocity and then denies that he is a 'speed freak'. I wonder what his definition of a 'speed freak' would be? Is this not a ballistic summersault. He tries to escape the testing of bullets at high velocity by saying that with some calibres the velocities were lower ... yes low velocity cartridges will not reach velocities of 2,700 to 3,100 fps. Don't misconstrue what I am trying to point out ... the examples I quoted is to be seen clearly on your website for e.g. 30-06 Spr and 300 Win Mag ... yes, I referred you to these .308 bullets, that were shot at high velocities ... not so?. In addition to this, HTL shoots it at close range and not at 200 to 300 yards to reach these "typical impact velocities" that he so cleverly refers to. Denial with a poor explanation. Shooting paper at point blank range(5 to 40 yards) at a velocity of near 3,100 fps is not near typical impact velocities my friend. How on earth can a soft nose bullet perform well at such a velocity ... that is the point that I am labouring. But the worst is ... it is not scientific to test a bullet outside its performance band and compare it with other bullets at differing velocities with differing constructions .... but he maintains he is not interested in anything less than scientific.

Then HTL finally writes, the point I have been labouring all along, ... "No one who actually reads my site will ever come away thinking that I am an advocate of the high velocity KE school of thought or that I think velocity is a good substitute for a controlled expansion bullet." In all my previous articles, I clearly and unequivocally recommend controlled expansion bullets in preference over the high velocity bullets that is self destructive as they loose more weight or even shatters. HTL sometimes says one thing then on another occasion, when he is cornered, he will swing around and say another thing ... so, the poor reader can float between 2 opinions ... this is what I am calling speaking with a forked tongue.

I trust I have proven my point.
Hope you enjoy this.
Chris

Physics amd mechanical engineering have been around for a long time. There is a reason that things are expressed the way they are in Resnick and Halliday: They have withstood rigorous inspection, by smart people, for a long time.

Any time somebody start making up formulas, equations, and new terms, he owes you a very rigorous, darn good reason why, and rigorous proof and demonstration of his work. That's a lot harder than understanding the existing texts.

The most frequent real reason for such stuff is that the writer does not understand the existing science.

Mehul, I first joined this forum several years ago, but have not participated in quite a long time, largely because it has too much of this sort of carrying on. I have not questioned who you are, I just couldn't tell who wrote what in your post.

I wrote what I did on this thread because someone asked the question. For some reason, you felt that was an unreasonable critique, despite the fact that I gave ample evidence that my judgment was well founded. No small arms bullet has 90,000 ft-lbs of energy. Force squared is a nonsensical quantity and it doesn't have the units of energy; force and energy are not the same. But most of all there is no basis for the theory in the first place - none at all. To say that this method is not meant to be scientific is double-talk. If you use scientific terms then you are accountable to get it right. My reasons for pointing this out are not personal and it would be equally true if someone else made the point.

Bekker knows very well the reason that I wrote to his editor (not to him) in the first place, as does everyone who saw the exchange that resulted. It was matter of journalistic ethics, not of science or terminal ballistics. My communication was private, but he and his editor saw it as a grand occasion for ballyhoo. Since he first publicly assailed me for my insistence that he not mis-use my material to bludgeon bullet manufacturer Gerard Schultz (rival to Bekker's pet local brand, Rhino), he has been very selective in his use of quotes and in choosing the context to use them.

What is ironic (and amusing) is that Bekker thought that my material was great stuff when he was borrowing from it for his own site and using it as a weapon against GS Custom, prior to my complaint. Since that time, in his eyes I am a pointy-headed academic - at best - removed from field experience. For that matter, I have published more photos of myself with dead animals and shown more personally recovered bullets than he (to my knowledge he has never done either - let the reader judge).

I refuse to ride on that merry-go-round for the amusement of Bekker or anyone else. The truth is its own evidence. I am content to let what I have stated stand and to let Bekker's own rebuttal serve as my defense. Smart people can draw their own judgments and either way that is OK by me.

Regards,
HTL

quote:

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Originally posted by Ulfhere (HTL):

I wrote what I did on this thread because someone asked the question. For some reason, you felt that was an unreasonable critique, despite the fact that I gave ample evidence that my judgment was well founded.

---

Ulfhere,

I have never ever said that anything that you posted was unreasonable - if you think that I did, show me where I said this. I have been clear right from the beginning that I do not know much about guns and am a learner. With that being the case, far be it for me to comment on theories of ballistics.

I have enjoyed reading differing opinions and debates that take place here (some vigorous ones, I may add) and my role here was only to post what was sent to me in e-mails. Whether you decide to contest another member's opinions or you don't is your previlege. Please don't attribute motives to me for none really exist.

I do not know enough to be involved in this debate personally.

Best wishes,

quote:

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One thing that has not been mentioned in these discussions that puts the whole premise posed by Mr. Bekker into question is the matter of conservation of angular momentum. What this principle states is that a rotating body will conserve the energy of rotation – if the diameter of the body is increased, the speed of rotation will decrease accordingly. This means that as a bullet begins to expand, the speed of rotation is reduced proportionally. The everyday example of this physical law is an ice skater spinning on the ice. If the skater extends their arms, the rotation slows to a crawl – as the skaters arms are drawn in tight to the body, the speed of rotation is increased to a blur. An expanding (expanded) bullet does not have the same rotational velocity as an unexpanded bullet.

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Essentially the point I made.

So mehurl. Your hunting experience is limited to 12 ga. shotguns but you have all these opinions anyway?

Uhhhhhhhhhhhhhj, ok. Whatever.

LAWCOP

Interesting I have similar experiences with 6,5X06 and 6,5X284. With 1-8 twist bullets weighing less than 120 grains of normal construction approximately 10% broke up before hitting the target.

quote:

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Originally posted by BBBruce:
Uhhhhhhhhhhhhhj, ok. Whatever.

---

BBBruce the criminal
I guess you have gained plenty of ballistic experiences while running from the law

Cheers,
/ JOHAN

BBBruce,

AT least I have the courage to accept what I do not know.

An arsewipe like you enjoys pontificating on subjects that you know nothing about on the Political forums.

One thing that I did come to know when I first read your posts was that you are an arsehole and this is something has proven itself many times over. I wonder if your knowledge of ballistics is as "learned" as your posts are about political affairs in the rest of the world.

Johan and Lawcop, IMHO I think you need to take in some shearing effects of the jacket by the fast rifling when shooting lighter bullets. You have quicker acceleration of the lighter projectile and more than likely less surface area (friction with the rifling), thus having the bullet shear instead of just starting to follow the rifling.

From Chris Bekker:

Harold,

If we want to isolate the effect of twist we need to step up the twist rate by changing to barrels with faster twists each time. With each barrel twist we need to push velocities with incremental steps. Shooting at 25 yds and again at 100 yds is not going to tell the story. The decay of angular velocity is hardly measurable up to 500 yards unlike the situation with forward velocity. Your reference to the Gary Sciuchetti tests is not going to help us and you cannot lean on his test, that had other objectives, to bolster your argument.. As the angular velocity is then preserved for quite a long distance, it stands to reason that its effect is applicable over practical hunting ranges and its terminal effect is as strong as when it leaves the muzzle. If we want to be scientific, we need to do a scientific test and define parameters for the test. It is that simple. but the project is more complex as rigorous testing is called for to be valid over a wide spectrum of bullets and a host of other variables, as I hinted in my very first post.

Furthermore, you now postulates (to accept as true as a basis for discussion although unproven) that the thermal load is the driver" and not the angular velocity as far as bullet fragmentation is concerned. You cannot lean on the situation of shooting copper bullets into steel and surmise that the heat generation that results is equally applicable when we shoot a lead-core bullet into flesh - I have retrieved bullets straight after firing them into an antelope and reaching temperatures of near melting point is not even a remote reality. You have not shown evidence nor convincing deductive reasoning as to why you blame the thermal load. The heat caused by the flame behind the bullet is definitely not a problem. I have never observed this in all the failed bullets that I shot. From this analogy, where you jump from the steel medium to the flesh medium you conclude that ... "In my view temperature is the key element, not angular velocity." I submit that it is your opinion (view) and not really a proven fact (not science). The HEAT SYNTHESIS is still unsubstantiated as far as I am concerned to properly explain the reason for fragmentation tendencies in conventional bullets in a hunting scenario. I should be back on this with more later on.

I do not know why you dwell on the rare occasion of bullet fragmentation in air as that only happens to a select few cartridges at extreme velocities (4,000 fps+). My point specifically refers to common bullet failure in conventional hunting bullets at typical impact velocities, when it makes contact with an animal. That is a different story, as the medium provides much greater resistance than air. Shear forces are involved on impact. Be clear on what I refer to - I refer to conventional bullets that are being sold by factories everyday - e.g. Speer, Sierra, Hornady Remington, Winchester, Norma, Sako, Sellier& Bellot, Privi, PMP, etc. These are all thin-jacketed bullets that are commonly in use for hunting of game and these outdated bullets (primitive design) cannot withstand present day velocities - both forward and rotational. I stated clearly that forward velocity is linked to rotational velocity and both are responsible for fragmentation. I also said that it is difficult to isolate the sole effect of excessive bullet spin, as more laboratory tests will have to be conducted to be more conclusive. The induced torque of bullet spin works 90 degrees against the forward force and that makes a huge difference - 180,000 to 200,000 rpm is by no means insignificant. If you still believe the spin velocity is slow and immaterial, consider moving an object by hand at 250+ fps. You can strip the head of a screw with a screwdriver real quick when it slips at a velocity much slower than this. I hope you can begin to see that rotational velocity can cause damage? Look again at the spiraled petals (proof that a bullet pins through an animal) of a retrieved Barnes-X bullet and try and bend those petals back - you cannot. That should give you an indication of the forces at work. If that happens with the strong petals of a Barnes-X, what do you think will happen to thin-jacketed bullets when we increase the spin rate? Once a bullet has been weakened by the deformation on impact, the centrifugal force is triggered and the bullet is torn open. It happens so fast that one can say it happens simultaneously. The faster a bullet spins, the more likely it is that the petals will fold, spiral or shed under the forces of bullet torque and tissue resistance. My formula was merely a method, admittedly non-scientific, but I said so myself from the beginning, just to express theoretical differences (not absolute differences) to enable me to compare - hope this is clear enough, and then comes my overriding comment ... it needs further lab testing to be conclusive. Fuckit man, I cannot make it clearer than this. What is important is that I observed something that is denied by scientists and those that just like to join the choir. It needs to be proven as I said, and I am going to spit on you scientists if I am proven right - if I am wrong, I will bow to superior knowledge. Until then, I will dig my heels in.

Conventional bullets work fine on game at impact velocities of around 2,000 fps, but at higher velocities their performance become progressively worse - see the excellent article written on tests done by Rick Jamison in Shooting Times, October 2002. If you do a quick scan of modern cartridges you will notice that impact velocities at 200 yards are way up from this level. E.g. a 7 mm Rem Mag that launches a 150 grainer at 3,100 fps will have a striking velocity of around 2,630 fps. It is the factories that are putting these frangible bullets in Magnum-sized cases for the non-suspecting (ignorant) public. It took the custom bullet makers to open the eyes of the factories towards the Mid 80's. Initially these same factories refuse to buy custom bullets from them. Federal was the first to be convinced that Nosler Partitions and Trophy Bonded Bear Claw bullets were a great advance in bullet design. Hunters that reload almost always opt for better bullets. I mentioned pertinently that factories make conventional bullets with equally thin copper jackets for both small calibers and bigger calibers, despite the increased energy levels - this is an inbuilt design weakness. That is why I advocate a move to stronger constructed bullets for hunting purposes. I have conducted a test some time ago with the copper-jacketed (not gilding metal) Claw bond-core bullets that are made in South Africa - very similar that the American made Hawk bullet. Claw's standard version comes with a wall thickness of 1 mm. As I was not happy with their weight retention ratio, I ordered it with 2-mm walls to avoid petals that shear off and to better protect the relatively soft inner lead-core. I shot both versions of the same bullet in my 9.3 x 62 with the same charge of powder. The wetpack had a 1-INCH dry telephone directory in front and the rest was soaked newspapers that I clamp down in a vice-type framework. I shot both bullets at relatively low velocities (2,250 -2,300 fps) through the same barrel, so there is no difference in twist rate here, but it shows that the thinner constructed bullet is more suseptible to the shear forces and torgue. These pictures speak a thousand words - the petals of the thin-jacketed bullet all sheared off.

Bullet Muzzle Velocity Retained weight % retained

270 gr Claw 2 mm 2,307 fps 266.2 gr 98.6%
286 gr Claw 1 mm 2,252 fps 119.2 gr 41.7%

PIC 1 (insert picture)

PIC 2 (insert picture)

If bullet spin was a non-event and of no significance whatsoever, FLIP NEL would not have complained about this phenomenon on AR. FLIP posted a question on the 16 th May 2002 about the effect of his 9,3 x 62 mm with an overly fast twist of 1-in-9 instead of the standard twist of 1-in-14 .... it reads as follows ... "My 9.3 x 62 do a lot of damage to large game like Eland and Kudu with shoulder shots, somebody said that the 9.3 x 62 don't normally do that and he thinks my 9.3's twist is to fast 1-9 and that makes the difference. Can it really make that a difference or what?" So you see, not even the slow forward velocity of a 9,3 x 62 can prevent bullet fragmentation when the twist is overly fast.

I have just located a man in a nearby town that owns a 9.3 x 62, but with a 1-in-10" twist as opposed to the standard twist of 1-in-14" that my rifle has. I plan to shoot the same bullets with the very same load in both, so we cannot blame the thermal effect. I am just busy for the next 5 weeks or so, but once I get a chance, I will be back with the pictures. Getting off the Merry-Go-Round is fine, but I am just getting on to the Roller Coaster now.

Until later and take care.
Chris

All of the above is not science - it is for entertainment only!