quote:

BUT, if you are shooting solids, the faster twist will tend to keep the bullet on a straight path after impact. For expanding bullets, the shape of the expanded portion has more to do with straight line penetration than does the twist rate.

quote:

My main reasons for a tighter twist is to avoid fish-tailing at short distance,

The opinion of two experienced men. I have to agree.

Pontificus Erroneus

Posted 21 March 2009 20:56 Hide Post

Can't buy Gerard's explanation.

"Slower twist barrels wear more slowly, build up jacket metal fouling more slowly and generate less chamber pressure at a given velocity level. But a barrel with a reasonable conservative SF will shoot well longer and in more varied conditions than one with a marginal SF. So be reasonably conservative, just don't get silly about it and think "if a little is good, more is better, and too much is just enough". A 1 in 8" or 9" .30-06 would have no advantage over 1 in 10" with existing projectiles and would have several disadvantages." ..... Razos Jack

How many buffalos and elephant have been shot at close range (25 to 50 yds) with a slow-twist of 1-in 14" in a 9,3 x 62 Mauser with great success over the last century? And in addition, up to the 80's hunting DG was mostly done with FMJ bullets with RN configurations. Today we have even better designs and much stronger monolithic Solids, and for another, with flat meplats, not prone to fish-tailing.

What we need to see is if there is indeed key-holing at say 25 yds in the .308 between a 10"-twist and an 8"-twsit with 145 gr GSC-FN Solids on a paper target for starters. This would be a very interesting excercise to conduct from which we can learn. And let the penny fall which ever way it wants, so that the truth can be defended, and not just opinions that have not really been tested.

Warrior

?

Alf,
In-target behaviour of a bullet is governed by the shape the bullet maintains or assumes in target. It follows that we can expect round nosed solid bullets to behave differently from truncated cone FN bullets. It is expected to see a different in-target result from deformation resistant military ogived bullets compared to ogived bullets that are designed to expand as they penetrate.

Your examples are for deformation resistant ogived projectiles (military ball), where the relationships between center of pressure, center of gravity, polar moment of inertia and the generated overturning moment, are different from that of hunting softs and FN solid types.

The closest to your examples would be a round nosed solid, where the relationship between the center of pressure and the center of gravity, in the absence of factors such as shoulder stabilisation and dart stabilisation, is approached, but still not close to being met.

However, in all penetration events of bullets of all types, in tissue or tissue simulant/replacement media, once the bullet is submerged in the media, gyroscopic stability becomes such a small factor, it can, in most cases be ignored. There is no dispute about that. I am at a loss why you continue to hold up examples of this type, when transition from flight to tissue is what is being discussed.

Your example serves only to show that military style spitser solids tumble as a result of their form and not as a result of what twist they are fired from. That is clear. What is also clear is that your examples hold true for military style spitser solids and has no bearing on the in-target behaviour of hunting bullets.

If you look at the results that you show, it is also clear that there is a huge disparity between the calculated, expected result and the actual observed result. The calculated explanation/prediction does not even closely match the practical, observed result. That is often the downfall of theory over practise.

Similarly, the example of boat tail / flat base bullets prove only that this difference in design is a factor when cavitation is present. Is this cavity formation or gas formation cavitation? In either case your example is again irrelevant because it tests the behaviour of non deforming ogived projectiles. This is not what we use in hunting.

Your examples are therefore not only irrelevant in this discussion of hunting bullets, but also explain why they are contrary to the observed results many of us see in practise.

I learned long ago that the pipe dream of what should be, is always tempered by the reality of what will be.

Pontificus Erroneus

quote:

The longer the bullet the longer it takes to tumble in target; Because the for the longer bullet has a greater axial moment of inertia for the same transvesre moment of inertia

Many moons ago Gregor Woods published an article in Man Magnum, where he made the observation that short stubby bullets tumble more easily in game than longer bullets (higher SD bullets). I just had to insert the term SD here for a bit of ballistic flavour. This seems to be in line with the above statement.

I must say I have never done tests of this sort myself (on game), as I have always been one for leaning towards the heavier bullets (on game), and they always worked well for me. So, I never bothered to consider short tubby bullets (on game). Come to think of it .... short and stubby can only be ugly. and I guess it gets increasingly ugly as we go up up in caliber when it reaches full bloom above .458 to whatever.

Rasputin then quickly tried to score a browny point to sight my test with mono-metals in a wetpack, which is not game. Also, by and large the SA hunter hunts mostly with jacketed Softs, and Greogor made his comment in that regard. Rasputin, you silly ass !!! Rasputin must always try to put another devious false spin on things to deceive, cast doubt and throw mud. Sorry Rasputin, you failed again !!! Come up with something more original and publish your tests for us on this subject matter - but please not how you see how differently the game fall - 50 animals with a slow twist, and then 50 animals with a fast twist - all that with the naked eye. Your super-natural power has us here in awe !!! Rasputin stuff !!!



Warrior

Pontificus Erroneus

quote:

A 1 in 8" or 9" .30-06 would have no advantage over 1 in 10" with existing projectiles and would have several disadvantages." ..... Razos Jack

The above should dumb it down for Rasputin, I think, but remain unconvinced, as Rasputin should always mesmerize his audience otherwise he is not true to himself.

And I have made a similar point recently with regard to the fitting of a 9"-twist, instead of the standard 14"-twist to a 9,3x62 mm. Going to a 12"-twist is still fine, but going over board to a 9"-twist is pulling the dam underneath the duck imo.



Warrior

Hey Warrior,
I see you agree that there are disadvantages to a 30-06 having a 9 or an 8 inch twist. What would those disadvantages be?

?

Alf,

quote:

Stick to the principle !

I am trying to but you keep on dragging in unrelated examples. Don't huff up now, that is my opinion so let me explain.

quote:

Your take: Fast twist barrels give longer Lnc's than slow twist barrels for the same bullet? yes?

No, that is not my take on this. The length of the narrow section of the wound channel (Lnc) is not twist dependent, when it occurs. It is dependent on the bullet shape upon impact and as the bullet changes shape during penetration. Non deforming, ogived bullets will tumble, round nosed, flat base bullets are prone to tumbling, FN bullets are fairly resistant to tumbling, mono softs tend not to tumble (if they open up and mushroom, which some do not do) and all bets are off on lead core softs and solids because they are unpredictable in their deformation.

quote:

So what you are saying is that the difference in angular velocity between two bullets fired from different twist barrels have an effect on in target stability assuming both impact at the same impact yaw angle.

The answer to your assumption of what I am saying is yes and no.
Yes - The direct implication of angular velocity differences is that the stability factor is different. This influences transition from flight and is not applicable to in-target movement.
No - The impact yaw angles cannot be the same because both fast and slow precession cycles will differ between two such bullets and this has a bearing on the angle of attack of the bullet.

quote:

ok how do we test and prove this point, First we have to standardise the bullet and conditions of the test as to negate confounding behaviours.

It has to be an ogived, non deforming, non fragmenting bullet.

This renders the test applicable to such bullets and Impala bullets and irrelevant to this discussion, the reason is below:

quote:

Why ? because if it deforms ie mushrooms it assumes a different mode of stabilization.

Of course, to this we must ad shoulder stabilisation and cavitation (forming of gas, not poking a hole) as seen with FN and cylinder shapes.

quote:

Bullets that mushroom are stable, they do not tumble!

There are conditions to this, it does not always happen. I now what is supposed to happen, according to theory, but there has been a gap in the theory called transition from flight. Published theory does not include transition from flight and I cannot find anyone else working on it. If you know of any literature in this regard, I would be grateful to see it. Note that my attention is specific: The time from bullet contact with the target to bullet fully submerged in the target.

quote:

So this was tested,

With non deforming spitser bullets, rendering the results applicable to such bullets and Impala bullets and irrelevant to the application of deforming hunting bullets.

quote:

not by observation in the field which btw represents a level 5 ( anecdotal) level of evidence

Level 5 then tells us what is actually happening - in practical application and physical result, if the sample is big enough.

quote:

but in a level 1 level of evidence test. Level 1 evidence trumps level 5 evidence !

Not when the level 5 evidence is the actual observation, relevant to the topic and the level 1 evidence is irrelevant to the topic.

quote:

Not only this your observation's in the field say nothing of this phenomeon unless you have x-ray eyes that can break down an event into a series of shots that take less than 1.5 milliseconds to conclude RollEyes

I say nothing about the phenomenon because I do not have x-ray eyes. That should be obvious. So I take this as an irrelevant snide comment and to be disregarded. (Have you been talking to Warrior?)

quote:

Fast twist barrels will give by calculation, within the range needed for the bullet to go to sleep (+/- 60m) smaller impact yaw angles than slower twist barrels based on calculation.

What is the result when yaw angles at impact are decreased? I know what it is but you need to tell us so that it does not come from me.

quote:

Actual measurement of the Lnc by high speed photography showed no difference between the fast and slow twist barrels.

Score: Physical observation - 1. Calculation/prediction - 0. It also proves that post impact bullet shape is the governing factor once the bullet is submerged in the target and other factors are of lesser importance.

quote:

The rotational Kinetic energy of a projectile is about 3/1000 of the total kinetic energy of the bullet. For a standard 30 cal 9.5gm bullet doing 830m/s linear velocity, angualr velocity of 17,100 rad/sec we have linear kinetic energy of 3272 joule and only 9 joule rotational kinetic energy That is 6.63 foot pounds against 2,413 foot pounds. So please explain how a fast twist barrel vs slow twist is going to influence the projectile behaviour in target ?

Why would such an insignificant difference in kinetic energy have any influence on on bullet behaviour in-target. Anyone who thinks that, does not know the role of Ke in the bullet penetration event.
However, your calculations do show that rate of twist also has an insignificant effect on chamber pressure, muzzle velocity and a number of other small considerations. (Pontificus Erroneus, take note. I know you do not understand what is going on but regard this as a CLUE.)

quote:

As to the issue of the BT and the FB all projectiles cavitate if they did not it would be a riccochet this is what bullets do.

You are talking about the bullet poking a hole in tissue. I am talking about gas formation. All bullets poke holes in tissue. Some bullets do not cavitate as readily as others.


V Varrior,
You are wasting your time asking. He does not know, he agrees because he thinks the quote conveys an opinion contrary to mine.

Pontificus Erroneus

quote:

I say nothing about the phenomenon because I do not have x-ray eyes. That should be obvious. So I take this as an irrelevant snide comment and to be disregarded. (Have you been talking to Warrior?)

Rasputin,

With this confession then, we can only conclude that is has to be the posession of pchycic abilities of a clairvoiant that is part and parcel of the make-up similar to the Russian Rasputin. We have have been told right here on AR how clear it should be if you see 50 animals fall this way, and another 50 animals fall that way.

Now before rasputin denies again that he said so, I want to quote him for ease of refernce ...

"The simple fact is that when 50 animals are shot with a bullet with a certain set of attributes and another 50 are shot with something else, the difference in fall down result is easy to observe by counting on the fingers of one hand."

If I may say something ... it is just a pack of lies and utter conjecture present in your own mind, and you believe youreself this to be true.



Warrior

Pontificus Erroneus

quote:

I now what is supposed to happen, according to theory, but there has been a gap in the theory called transition from flight. Published theory does not include transition from flight and I cannot find anyone else working on it.

Rasputin,

I am curious to know how this 'gap' was discovered.
What was the process and methodology of discovery?
When was this discovery made?
After discovery, how did you link it to different levels of SF?
Were SF values taken at range as SF values increase down range or irrespective of range?

I still find it astonishing that you believe there could be a difference between a 9,3 FN bullet and a 9.5 mm FN bullet (.375") for reliable straight-line penetration - having an absolute minimum of SF = 2 and SF = 2.5 respectively for these two bullets. If there is scientific logic or a mathematical calculation how these break-points were deteremined, for inclusion in systematic design parameters throughout the caliber range, it would really be very helpful in terminal ballistic literature.

Could it be that this gap is actually the gap between your ears?

And this brings me back to Alf's previous question posted some time ago:


Posted 21 March 2009 10:29

"Gerard:

I'm trying to figure this out ? why would your 30 cal bullet with a S value of only 1.1 at muzzle be be a problem in hunting ?

If we calculate the SF value it becomes more stable over distance untill the bullet goes transsonic, the slower it goes the more stable it becomes as long as it remains supersonic. As a long as that bullet is statically stable it should not be a problem.

Let us see real time values for a 30 cal doing 2700 at muzzle with a SF = 1.3 at muzzle and angular velocity of 2729 rad/sec will have a SF of 2.29 at 300m doing 2020fps and 2614 rad/sec angular velocity.

The angle of attack ( SQ rt of the yaw plus pitch) of a 30 cal 168 gr match bullet at 600 m is about 2 deg with a SF value of about 3.2 So what i'm trying to figure is why you claim this to be a problem?" ..... ALF

Pontificus Erroneus

Rasputin,

Most people would jump at the opportunity to share their discoveries with the world and became famous - so be an Edison or a Columbus and give us an introductory lecture on the ground-breaking discovery of yours that no one else in the world seems to be working on in their labs. The glory is all yours, but if it does not come out in understandable form, you would never get the fame for your pioneering work.

Therefore, more members will benefit from your eloquent explanations, even if I do not understand, so they can spread the word. And remember, it is all in the explanation !!!



Warrior

Hey Warrior,
You don't get out much, do you?

?

I'm reading with great interest the discussion that is developing although my impression is that we are drifting away from the original topic.

I've been reloading for a number of years (more than 40) and my first 30 caliber rifle I bought in 1973 (it was a 30 06).

During the '80s I bought my first 308 (a standard barrel Sako) that I used extensively untill I traded in for a semicustom 270 build for me in 1992.

The 308 that I'm now rebarreling (an "Israeli Mauser K98) was bought in 1994, to be used as a "pig gun".

The barrel was shortend to 18" and the gun is accurate with 130 grains bullets but it is fish-tailing with longer bullets well over 100 yards. It is grouping again at about 200 yards.

I do not run after pigs any more but I can use a light open sight gun for hunting meat in the bush, from warthog to kudu.

I want to be able to use heavier bullets than 130 grains (I have a good stock of 150 and 170 grains)and I want to secure the best short range stabilization because (in my opinion) a bullet that is stil fish-tailing is more easily deflected by foliage and it will be more prone to tumble on impact.

I'm aware that overspinning a conventional bullet will cause instability but the problem will be minimal with lathe turned bullets.

In the remote case that I will be charged by some dangerous animal I also want to have in the magazine the most effective short range load that is possible fot the 308 Win.

In my mind it will be a short flat nose lathe turned copper bullet, pushed at the maximum speed and slightly overstabilized in order to increase the chances of a straigh on-line penetration.

Based on your advices, the best twist rate for my requirement is going to be 1:10 as 1:8 will probably creating problems of overstabilization with the conventional 150 grains bullets at moderate velocity that I will be using most of the time.

I noticed that some of the members that consider 1:12 an adequate twist on a 308 Win. apparently do not have personal experience of shooting this caliber on a very short barrel, accept 2" grouping at 90 yards as a reasonable accuracy, do not considere foliage deflection as a very important problem and do not give enough attention to the in-line penetration required for the "defensive" load.

I respect Grgory Wood opinions but I've seen too many long bullets tumbling or changing course inside the animal to believe that a long bullet will give me any significant advantage in schooting a dangerous animal at few paces distance.

Can I reasonably conclude that in my case 1:12 twist is not enough (by my own experience) and 1:8 will be to tight for the bullets that I'm more likely to use? Therefore the conclusion can only be 1:10 twist.

I'm currently waiting for the permit to repalce the barrel and as soon the job will be finished I will report on performance.

Thanks to all

quote:

Originally posted by Andrea Sandri-Boriani:
...my impression is that we are drifting away from the original topic. ...

Hey Andrea, There is a valid reason for the "drifting" - two of the participants don't have a clue as to what they are posting. And that is creating the confusion, just as it always does.

I've been wondering if you were able to see through it for what it was and obviously you have. I'd recommend you just go back and re-read Gerard's posts which address "your" specific questions prior to the alf and the warrior .

Nice catch!

Good Hunting and clean 1-shot Kills with the new barrel.

Andrea,

Your reasoning is sound for what you want to do.

1. Your need for having a solid is understood, and the 145 gr GS-FN will be the best choice you can make as most manufacturers do not offer a solid in .308 cal, let alone a solid in FN configuration.

2. Momolithic Solids cannot to be too long, because of the overturning moment issue, and that is why the lighter Solid of only 145 gr vs the traditional weight of 180 gr is a sound decision.

3. Gregor Woods referred to jacketed Softs and not monolithic solids. It is genrally accepted and proven by now that long monolithic Solids with round noses veer off course earlier, and are thus more prone to tumbling especially where deep penetration is a critical element, such as in buffalo and elephant.

For the above the 10" twist is the ticket.

Regards
Warrior

quote:

Do you read the rubbish you write? Reliability comes from the properties of a product, not from the observation of how the product performs.

Rasputin,

Wow, you can talk such utter rubbish, and then you twist your own garbage so it looks like I talk rubbish by throwing it over a language barrel. It just does not work. Now let us just explore this rubbish a bit further, this is what you said ...

On 3/11/2008 you wrote: "Entry level spec for our FN solids is a S/F of 2. Depending on speed and meplat area, some are pegged at more than 2.5 (to start with). The difference in reliability of linear penetration and depth, from S/F 2 to S/F 3 is very noticable. Only when S/F numbers exceed 3.5 to 4, is there no longer much observed difference in linearity and depth."

Then later in a reply to defend your position you said: "The simple fact is that when 50 animals are shot with a bullet with a certain set of attributes and another 50 are shot with something else, the difference in fall down result is easy to observe by counting on the fingers of one hand."

All along we see this thing about "is very noticeable", "observed difference", "difference in fall down result" and " easy to observe". and what then naturally follows is that you observe the reliability of your product, based on its propertties. Yes?... No? Should be yes, otherwise it is moot and no difference appreciable.

I still find it astonishing that you believe there could be a difference between a 9,3 FN bullet and a 9.5 mm FN bullet (.375") for reliable straight-line penetration - having an absolute minimum of SF = 2 and SF = 2.5 respectively for these two bullets. But is does not end here - if there is a fundamental logic to it, then it should flow through to the next caliber up, say the 10.56 mm bullet (.416"), the logic cannot just abruptly end by the 375 H&H in terms of a minimum required SF.

Again how were these break-points discovered .... by observation, by calculation, by inference or by guestimate?
Was it all by shooting game and then observe the fall down result?
Was this fall down result purely attributable due to different levels of SF?
As SF values increase down range did you do a back-calculation to bring the SF values back to the muzzle position?

This needs clarification ..... does the .375 bullet need a higher SF than the 9,3 bullet because it has a bigger MEPLAT AREA and a higher VELOCITY? What happens when only the meplat area differs, and we down load the 375 H&H to 9,3 velocites (say to 2,350 fps)? We do know that velocity play such a minute role in the SF caculation in the middle band of standard operating velocities, not so?

Warrior

?

Hot Core,

I would like to hear about your experience on 2 statements below that were made by Gerard at the beginning of this thread. If you do not have personal experience with regard to these 2 issues then an engineering opinion would suffice. Only by sharing experiences and the parting of acquired knowledge can we learn from each other. So in this spirit I would like to hear you out on the following issues:

1. "The 130gr HV outperforms jacketed lead bullets up to 220gr at short range, with better straight line penetration, deeper penetration and larger wound channel volumes."

2. "Slow and heavy deflects easier and is more prone to tumbling."

Just to lay the foundation before you answer, it is clear that the above refers to an expanding mono-metal bullet versus an expanding lead-core bullet. This is an apples to oranges comparison, but a decision that hunters have to make. Since the mono-metal bullet is of stronger construction it would only be fair to pick a strongly constructed controlled expansion bullet (CEB) such as say a Swift A-Frame bullet or a NF Soft as all of them are premium custom bullets. Let us pick a 200 gr Swift or NF bullet as that is the heaviest they make. Do you agree or disagree with the notion that the 130 gr HV bullet makes a larger wound track?

I would like your engineering motivation as to why you agree or disagree with statement number 2. Bear in mind that a CEB that is heavy-for-caliber (such as a 200 grainer) is shot at a lower velocity, still has a higher momentum value at practical range, mushrooms so that it COG point shifts forward, bound to keep its petals and not to be ripped off in the first 2 to 4 inches of penetration largely because of the much lower velocity ensuring to keep the bullet within its threshold strength. Why then would the CEB "deflect easier" and be "more prone to tumbling". Do these CEB have such a dismal reputation iro deflection and tumbling vis-a-vis the HV bullet that loses its petals due to a high striking velocity (ie light and fast)?

Alf is on about measuring these events, and that changes the subject then away from an opinion to controlled experimentation to get a handle on this nebulous issue that gets seemingly interpreted in different ways. We do have 2 schools of though here - "fast & light" and "slow & heavy" that will linger on for as long hunters persist not to switch over. To make this more practical, let us assume we use a 30-06 Spr that is perhaps still the most widely used cartridge, and let us say we are after Elk/Eland sized game. Which bullet would you choose? Another issue that would naturally surface is the bone smashing ability of the bullet in question and its terminal momentum; accounting for weight loss at impact during the first few inches before vital organs are reached.

Your honest answer is appreciated.

Thanks
Warrior

Watch out Hot Core, this is a trap. Gerard warns of this. Warrior is having "lucid moments".


Hey Warrior,
You still havn't said anything about the crow questions.

Trax,
The call sign is ok. What is a bit more confusion amongst the already confused. Most days I do not know my kneebone from my elbow and it is all in good fun anyway.

quote:

Originally posted by VVarrior:
Watch out Hot Core, this is a trap. Gerard warns of this. Warrior is having "lucid moments". ...

Perhaps a bit of witty Sarcasm?

Do you remember the thread where warrior stated that a Jacketed Lead Bullet wouldn't Kill an Elk(or blathering to that effect)? Can't remember if alf was in that long-ago thread or not. But if he was I feel sure he included something about people being shot - as if it had ANY relevance. Pitiful!

Hot Core,

Hot headed as always and pure crap that your are talking here. All bullets can kill - even a .22 bullet at 20 yds can kill an elk if shot in the head. Your twisting of words are pitful.

Please stay on the subject and answer the questions. If you do not wish to contribute to this discussion, then fine, but then your snide remarks against Alf and me is not appreciated and couter productive.

You were challenged by Alf and now you run away like a coward without defending your position, why?.

From my point of view, I afforded you an opportunity to answer 2 simple questions, but instead you elect to change the subject in another direction and hide behind the bush like a jackal to obscure your position. I will respect your right to differ with me or Alf, and will also defend your right to do so. Since you chose to declare a difference of opinion with Alf and myself, you are being called out so we can see where you stand and why you stand there. That is pretty simple.

To elaborate on the terminal momentum, here is the position at 200 yds yds, assuming the HV bullet would lose all its petals (16%) at high impact velocity as it is bound to do so above around 2500 fps starting off with max published velocity, and the Swift A-Frame bullet would almost retain all its weight @ 98% at such moderate velocity and expand nicely to twice original diameter with intact petals:

Bullet ------------------------ BC -------- MV -------- Mo --- Impact Vel @ 200 yds --- Retained Weight ----- Terminal Mo
130 gr HV ------------------ .370 --- 3,300 fps -- 61.3 -------- 2,770 fps ------------- @ 84% = 109.2 gr --- 43.2 Lbs/ft-sec
200 Gr Swift A-Frame ---- .444 --- 2,550 fps -- 72.9 -------- 2,172 fps ------------- @ 98% = 196.0 gr --- 60.8 Lbs/ft-sec




Warrior

Alf,
Your first post of 6 July applies.

You said that fast twist barrels will give smaller impact yaw angles than slow twist barrels. I asked:

quote:

What is the result when yaw angles at impact are decreased? I know what it is but you need to tell us so that, for Warrior's benefit, it does not come from me.

In your reply You say:

quote:

most of the current large scale overviews of the wounding process cover the transition from flight to target.

You follow that with a huge amount of explanation and, after going through all of it, I do not find anything about the transition from flight to tissue. All I find are facts dealing with penetration in-target and more facts about non deforming mil ball style bullets penetrating in-target and how the Lnc is affected by the yaw angle. This is not relevant to our discussion which deals with bullets that mushroom during penetration.

The length of the narrow channel is determined by the impact yaw angle and how the bullet reacts to the deceleration force. If it is non deforming and ogived, it will tumble at some point. If it mushrooms or is shoulder stabilised, it usually does not tumble and the length of the narrow channel is a non event, because there is none, in the context of the studies you present. With hunting bullets the Lnc, such as it is, is determined by numerous more important factors than yaw angle at impact.

What is relevant is the question I asked about the effect of impact yaw angles. I did not ask the question for the hell of it, how about having the courtesy to answer?

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

Your second post of 6 July applies.

You ask:

quote:

Wound channel volumes larger, were they measured or is this conjecture and sales talk?

In an article in Magnum Magazine Koos Barnard compared the results of firing 150gr HV bullets and jacketed lead 200gr bullets into wetpack. He used his 30-06 and the article commemorated 100 years of the 30-06 cartridge. He found that the 150gr bullet went an average of 5cm deeper and returned a larger volume wound channel than the 200gr lead core. This confirmed what I find in testing during design. It is also confirmed by what customers experienced who have used both styles (light fast HV and slow heavy lead core) in practice, on game, in bush hunting. Several of them are PHs. One in particular used the GSC 130gr HV, compared to lead core bullets of 180gr, 200gr and 220gr in his 30-06. Lastly, it agrees with my own experience of bush hunting of kudu with 130gr HV bullets compared to two types of premium lead core bullets of 173/175gr (7x57 with a 1:8" twist).

You say:

quote:

This attack on "common convention" as having no basis in fact pretty bold would you not say given the weight of evidence in ballistscs literature?????

You misquote me. I said: "This is one of those cases where conventional thinking has no basis in fact, when it comes to mono bullets." Show me where my statement is contradicted in a discussion of mono expanding bullets.

You ask:

quote:

Ouch, SF factors determine brush busting ability ?

Why do you find it strange that I dare venture into uncharted territory to find solutions? Must all bullet makers slavishly follow established convention and not try to find solutions to problems? Have you ever seen a target like this five shot group below? (Two bullets were destabilised at the muzzle and the coin is 20mm/0.79" in diameter)



Why not take what I say at face value and ask me questions, instead of questioning what I say? There is a difference and I think I am beyond the stage where I am feeling around in the dark like I did 15 years ago. Had I continued doing what has been done before, would there have been a bunch of manufacturers making drive band, grooved, multi-cannelured and flat nosed bullets today?

You ask:

quote:

Always penetrate deeper????? methinks always is a very big word in this neck of the woods ?

You left out "straighter" but you have answered this yourself previously: Penetration depth is increased when yaw in-target is decreased and/or forward contact area is reduced and/or the center of gravity is forward of the physical center and/or the bullet is shoulder stabilised. These are the properties a light for caliber HV has when impacting at close range. Many of these properties are absent when a heavy lead core of the same caliber impacts and deforms.

You say:

quote:

No! not so what if I choose to use a denser bullet material

Factually you are correct but you are out of context. My remarks about the four ways to increase SF was in the context of monos. Read the entire mail and you will see this.

You ask:

quote:

Since when is SF the only factor that detrmines stability??????

In the context of my reply to Andrea, it is the one that matters. The other factors around stability are irrelevant because we are talking short distance (maximum 150m), mono construction (statically stable). Tractibility does not enter into discussions of shooting at spitting distance. Stability factor is the criterion that is of interest to the reloader, the remainder of criteria are the responsibility of the bullet designer. What else do you figure I should have mentioned? Please do not quote issues relevant to artillery fire at 35Km.

You ask:

quote:

and how do you explain what happens when SF is negated by the density of the target?

This must surely be at least the tenth time that I say to you: Stability factor is of no importance once the bullet is fully submerged in the target. Why do you continually infer that I hold that erroneus opinion? I have never said that SF is a factor during penetration in-target, why must I explain it?

Do me the courtesy of reading my replies and responding to my questions, that way we do not have to cover the same ground over and over.

Hot Core,
Lucidity has evaporated?

quote:

pure crap that your are talking here......even a .22 bullet at 20 yds can kill an elk...........Your twisting of words are pitful......your snide remarks against Alf and me is not appreciated........now you run away like a coward ...........hide behind the bush like a jackal to obscure your position............you are being called out so we can see where you stand and why you stand there...........

Hey Warrior,

quote:

Bullet ------------------------ BC -------- MV -------- Mo --- Impact Vel @ 200 yds --- Retained Weight ----- Terminal Mo
130 gr HV ------------------ .370 --- 3,300 fps -- 61.3 -------- 2,770 fps ------------- @ 84% = 109.2 gr --- 43.2 Lbs/ft-sec
200 Gr Swift A-Frame ---- .444 --- 2,550 fps -- 72.9 -------- 2,172 fps ------------- @ 98% = 196.0 gr --- 60.8 Lbs/ft-sec

I see you consider bush hunting as 200 yards.

The original question was asked "Most of my shots are taken below 90 yards" so if you run those numbers for 100 yards:

Bullet ------------------------ BC -------- MV -------- Mo --- Impact Vel@100 yds --- Retained Weight ----- Terminal Mo
130 gr HV ------------------ .370 --- 3,300 fps -- 61.3 -------- 2,985 fps ------------- @ 84% = 109.2 gr --- 47 Lbs/ft-sec
200 Gr Swift A-Frame ---- .444 --- 2,550 fps -- 72.9 -------- 2,340 fps ------------- @ 98% = 196.0 gr --- 66 Lbs/ft-sec

Going by what you have taught us: "Momentum traps bullet weight & velocity and the XSA is the factor that applies the brakes." And also this pearl of truth: "And that is also why the ratio of Mo/Xsa is a superior measure over just SD when we judge penetration ability. That is force applied over frontal area,"

Using your assumption that "assuming the HV bullet would lose all its petals" it would leave a caliber diameter bullet shank. The Swift bullet "would almost retain all its weight @ 98% at such moderate velocity and expand nicely to twice original diameter".

This wisdom, when applied to the numbers at 100 meters show a factor of 47 for the penetration of the GS 130gr bullet and a factor of 33 for the Swift 200gr bullet. Your teaching therefore predicts that the 130gr bullet will have an extra 42% penetration. Wow, that is incredible. The two of you actually agree for once because Gerard said that the 130 grain turned bullet gives deeper penetration than 200 grain jacketed bullets.

Way to go, what?

I just thought of something. How would the momentum of a penetrating bullet be quantified. In accident reconstruction, depending on circumstances, it is usual to take the mass at the start of a collision together with the residual mass to arrive at an average to work with.

On that assumption, the average for the 130gr GS bullet is 120gr and that of the Swift would be 199gr. Using the method that Warrior showed us, that means the factor predicting penetration is 51 v 33. That means the GS bullet will have a 55% penetration advantage over the Swift bullet.

Warrior, you old dog, you have been arguing for GS bullets all the time. Here we thought you are in favour of slow, heavy bullets.

Surprise! Surprise! Surprise!, as my hero Gomer used to say. I didn't think there was any chance at all that I'd saved a link to "warrior claims that 0.458" Bullets break-up when used on Elk. Now today he calims, " even a .22 bullet at 20 yds can kill an elk".

Had no idea I'd saved a link to his original claim because it is w-a-y too stupid for anyone understanding the barest modicum of Ballistics or Hunting to comprehend where his "Lucidity" was back then. Now I see according to warrior's hero VVarrior that what little he had has evaporated.

I'll let you all decide if (my hero)warrior is worth listening to. As for me, I knew the answer to that back when he posted about the 0.458" Bullets.
-----

Hey VV, I need to save a link to this one too. No telling what my hero will come up with next.

And Gerard just keeps "baiting them in".

?

Ah, the refrain from that old Dire Straits number "Heavy Fuel" is buzzing in my head now.

quote:

Alf: You say, so does Warrior that faster and lighter penetrates better than slower and heavier for the same momentum if i'm not mistaken

Er........ no, I think we are saying

quote:

Him Warrior: Mo/Xsa is a superior measure over just SD when we judge penetration ability. That is force applied over frontal area

Warrior will back me up on this.

quote:

Alf: if we keep momentum the same for two bullets one light and one heavy, both keep their reference wetted areas the same diameter, the one has to be faster than the other, Not so?

Er....... no, I think we are saying

quote:

Me VVarrior quoting Him Warrior: the HV bullet would lose all its petals" it would leave a caliber diameter bullet shank. The Swift bullet "would almost retain all its weight @ 98% at such moderate velocity and expand nicely to twice original diameter

one bullet is twice the diameter of the other, not the same diameter.

However, I am flabbergasted at some of the titbits you tantalise us with.

"the light fast bullet dumps more energy per unit distance travelled" So: Speed results in large diameter wounds.
"Light, fast, spheres gave shallow large "wounds" in gelatine" So: Large diameter wounds, but shallower than the heavy spheres, because the spheres are the same diameter.
"The greater the force per reference area the deeper the penetration" So: This is what Warrior said!!!! Double caliber diameter is four times the surface area and needs four times as much force to move it along compared to one caliber diameter.

Therefore, If the fellows Barnard, Gerard, Quoted Professional Hunters et al were correct in their anecdotal evidence that the light GS bullets went deeper and straighter than the lead core bullets and produced larger volume wound cavities, and the scientists Alf and Warrior are correct in the paper they present, there can be only one explanation:

1. The bullets arrive on target: One is light and flying, the other is heavy and trundling along sedately.
2. The light bullet mushrooms to double caliber and dumps a load of energy because of the speed. This gives a large volume wound at that point.
3. The heavy bullet mushrooms to double caliber and dumps less energy because of its slowness. This gives a smaller diameter wound cavity at that point.
4. The light bullet loses the mushroom to become one caliber in diameter and slows down.
5. The heavy bullet remains double caliber because it lazy pace will not allow shedding of the mushroom and the large mushroom puts four times larger brakes on it and it does not have four times the momentum so it stops.
4. The light bullet, now at a quarter of the frontal area of the heavy bullet, continues deeper before it stops.

Logically, according to the science and anecdotal evidence presented here, the light fast bullet must produce the larger volume wound and go deeper.

It is a miracle!!! Alf, Warrior and Gerard all agree!!!! What do you say to that Hot Core???

My most humble apologies to Alf. I have been severely chastised for saying this

quote:

and the scientists Alf and Warrior are correct in the paper they present

It has been pointed out to me that Alf presents the paper and Warrior agrees, he does not present and his scientific standing is doubtful. Regardless, it is good to have harmony and peace amongst the gentlemen here.

?

Alf,

1. What is the result on penetration when yaw angles at impact are decreased?

2. You say:

quote:

most of the current large scale overviews of the wounding process cover the transition from flight to target.

Where would I see reference to this?
3. Regarding stability: What else do you figure should I have mentioned to Andrea in the context of what matters for him to make a choice?
4. Are we clear on the fact that stability factor has little effect once the bullet is submerged in the target?

Thanks

What we typically see in the field is that double caliber expansion of CEB's, such as NF, Swift, TBBC & Rhino bullets, is that the bullet is retrieved on the opposite side near or under the skin of kudu sized animals and that is easily 48 cm (about 19 inches) and more, depending on angle of shot and type of flesh and bone encountered along its path. What is critical in the killing event is when the bullet pass through the vital organs, and let us assume it is the position of the heart/lungs for argument sake - not the few inches before the vitals are reached and not the distance beyond the vitals.

Like wise, it is quite typical that the HV bullet goes right trough, by virtue of being a caliber-sized cylinder after loss of petals, as the ratio of Mo/Xsa is optimised after the stage when the petals mushroomed and got ripped off - that stands to reason. Any penetration beyond the animal (air in wide open spaces) means nothing anymore and is moot. We must remember that Mo/XSA is just a yardstick and not perfect, as momentum cannot just be made up any way we like, as at extreme ends of the velocity spectrum the increased velocity will experience increased drag by the tune of the 'square of velocity', which is not easily trapped by such a simple statistic, and like wise if the velocity is so low that it becomes a bump instead of actually penetrating skin.

What is important though, is the permanent cavity that is being crushed by double caliber expansion of CEB's vs single caliber sized holes of the HV bullet after loss of petals. The temporary cavity happens due to the elasticity of flesh that plays an insignificant role in the killing event relative to the permanent cavity - and the higher the energy of the bullet that is being dumped the bigger the temporary cavity will be. The HV bullet, which effectively becomes a lighter FN Solid after loss of petals, cannot create a bigger permanent hole than an expanding bullet, as that is the very logic why bullet manufacturers make expanding bullets, and more so CEB's, as they are more effective on game than solids. Solids have been designed with extreme penetration in mind, and that is another application. So I need to see the evidence of this claim that the HV can supposedly create a bigger wound channel.

So we actually need to look at the wound track volume, and save for the first 4 inches, the CEB would crush a bigger permanent wound channel for say the next 15 inches (38.1 cm) in our theoretical example, and when you calculate the volume of that cylinder (wound channel), you will see it far exceeds the volume of the HV cylinder (wound channel). Based on this, I hold the view that a CEB is better. Alf, being a medical doctor, is the expert on how wounds are created and the interpretation thereof, and he can correct me if I am wrong, but as the light shines for me now, I am not convinced that the mechanism of the lighter HV bullet has made heavier CEB's redundant by virtue of their superiority in the killing event.

Warrior

Andrea, I would suggest that the down-loaded 9.3 which groups well is probably the best choice, since it is loaded with solids underneath that. I am not sure what dangerous game you have around, but would think buff, and rhino maybe? It sounds like the bush is quite thick where you hunt and normal shot distances are short. If the magnification of the scope is low, say around 2X, then great. If I was walking around thick bushveld with dangerous game around with a .308, I would prefer it to be a R1/FAL! I do not think that you are going to get around bullet deflection by grass, twigs, etc if you step down in calibre anyway. If you have a fair amount of .308 bullets already, use them in your rifle as long as they can keep some sort of group. Do the bullets actually keyhole at close range? To be honest, as long as they stabilize some-what, I am sure the pig/impala/kudu will not notice the difference!

Major angst all round. Alf, Warrior and Gerard still do not agree. I do confess that I am confused.


Alf,

quote:

Please. Get one thing straight, I have no connection or affiliation to anyone or product anywhere, that means I'm not an agent for Warrior or any bullet company or product.

Did I say that? I did not say that. I am sure I did not even allude to that. Where did you get that?

Thank you so much for explaining about gelatine and muscle tissue. As I understand it, your earlier reference to gelatine (the one I quoted) and where you said "Light, fast, spheres gave shallow large "wounds" in gelatine, slow heavy Spheres gave deep narrow wounds in gelatine for the same momentum." must be read together with "recent high speed flash radiographs have shown that the TC in muscle is in fact larger than the expanded tract in the gelatine"

From that I draw the conclusion that light fast bullets make bigger holes in muscle than in gelatine. (That makes an even more convincing argument for light fast bullets.) Is this conclusion right or wrong? Do I understand your explanation correctly and in context?

You also say that the gelatine test was done with steel spheres. Heavy spheres and light spheres. This means that the light spheres were smaller in diameter than the heavy spheres. Unless they were hollow but then they would be properly described as balls. Were they balls? Let me know otherwise what follows will not hold water.

The steel sphere test found that light, small diameter spheres going fast, made much larger diameter holes than larger diameter, heavier steel spheres going slow. Heavy spheres went deeper than light spheres.

quote:

The conclusion is and remains undisputed:

The greater the sectional density the deeper the penetration but the smaller the temporary cavity in visco elastic materials

Now this is what confuses me. The sectional density of a steel sphere is always the same, regardless of what diameter it is. How can a test with steel spheres, all of the same sectional density, prove that differences in sectional density result in different depths of penetration?

My confusion becomes greater!!

When you said

"the light fast bullet dumps more energy per unit distance travelled"
"Light, fast, spheres gave shallow large "wounds" in gelatine"
"The greater the force per reference area the deeper the penetration"

I believed that you meant to say

"the light fast bullet dumps more energy per unit distance travelled"
"Light, fast, spheres gave shallow large "wounds" in gelatine"
"The greater the force per reference area the deeper the penetration"

I must have been mistaken. I would appreciate it if you would perhaps put the meaning of the above in clearer terms so that I may comprehend and understand what it is that you really mean.

quote:

Now today he calims, " even a .22 bullet at 20 yds can kill an elk".

Hot Core,

You are out of context completely, why do you drop off the last bit of my sentence? This is what I said, and if you disagree with it it shows your ignorance ... "All bullets can kill - even a .22 bullet at 20 yds can kill an elk if shot in the head"

As for the .458 bullets, again you twist what I said by stating .... "warrior claims that 0.458" Bullets break-up when used on Elk." ... to suit your sly tactics. I specifically referred to conventional bullets that are brittle that cannot withstand the force of impact, not the stronger constructed bullets. And I even showed you a photo of failed Claw bullets and also how these same Claw bullets were improved. This may be a refresher for you ... Posted 24 May 2008 15:07

http://forums.accuratereloadin...=103109868#103109868

I talk about what I have seen, and will not ever use conventional bullets that pose the slightest risk if there is an ubandance of much better premium bullets that are readily available. This is my choice, and a wise one at that. If you do not trust me, ask my friend Gerard to educate you on frangible conventional bullets.

Warrior

"If we look at the temporary cavitation phenomenon in Wounds we see the greater the velocity the greater the temporary cavity diameter but the shallower the penetration. If we increase a theoretical non deforming stable projectile in target we see that the TC increases in size but penetration decreases. Eventually we would have a very shallow wound with very large TC." ... Alf ( Posted 04 March 2008 )

Alf,

Please bear with all of us, the collective group that have no medical background like you, and explain even in greater detail the wounding effect. We can all learn in this department as it is not our bread and butter like it is yours, and more specifically that you have gone deeper in to this aspect than most other doctors. We as laymen can only learn from you in this regard and I truely think there is a crying need by most hunters to better understand. If I remember correctly you mentioned that even the medical profession had it wrong up until recently. This must be a pain for you to talk to us poor mortals, ESPECIALLY VVARIOR, WHO MIGHT JUST CLAIM THAT THE ABOVE QUOTATION IS NOT CLEAR, AS IT IS A STATEMENT AND NOT AN EXPLANATION .

Warrior