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Alf, I doubt Vapodog meant insult with his post, I surely didn't. And you gotta admit, it was pretty darn funny, given your often long winded and detailed responses. No matter whether they are correct or incorrect or whether I think one way or another, they can be a hoot. As far as Warrior, I used to think Gerrard was being too hard on him, but experience has taught me that that is not the case. Perhaps Gerrard might tone down the name calling, but I have to say that Warrior can bring that out of even a Saint, and I can understand Gerrard's frustration. Not that anyone gives a damn what my opinion is... JPK JPK Free 500grains | |||
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WARNING!! HERE CONTINUES A  THAT EXTENDS TO THE END OF THE THREADWarrior/Truvelloshooter/Chris Bek,
I do apologise. I assumed you googled the information but accept that you "borrowed" from Alf. I know that Original thought/research is not your strong point and neither is comprehension of that which you "borrow".
I have an answer but accept that there may be more than one explanation, or additional information that may be useful. From Alf it will probably be well researched but, from you, it will probably be hillarious.
Ooooh! Big time paranoia. Proves you don't know the answer.
What would be the point? Every time I have answered a question, asked by you, you have rejected it in favour of some crackpot idea you hatched after smoking your socks.
Don't make me laugh - you are incapable of learning anything.
Really big time paranoia!!! It is a statement of fact for which an explanation is required. Similar to: "Bek is losing his mind and is becoming increasingly paranoid. What could be the cause?" As with my question above, I have some theory but there may be other points of view I have not considered.
Yet you constantly call on others for their opinion, pictures and research. What makes you the only person allowed to do that? Which brings us to the questions you have left unanswered: 1. Chris, see the capital H in the circle in the formula. What do you think it means? 2. Who manufactures a hunting bullet, that flies with its nose up at hunting ranges of 200 to 500, with a muzzle s/f of 5? (The lame explanation you gave Alf on this one fools no one but it will suffice for now.) 3. It would be interesting to see what you would offer as proof of this "myth" of transitional stability? Some research perhaps, or some comparative testing? Maybe another's noted opinion based on a smidgen of research or testing? 4. Forgive me for adding a fourth question that you cannot answer: With this imaginary bullet in question 2, what would the angle of departure of the bullet axis be, compared to the line of sight, for a 500m zero? You know, give us some idea of how terribly "nose up" such a bullet would fly on its way to the 500 mark. Alf, It is a pity that Bekker gets in the way of useful discussion but, by now, we should be used to it. Yes it is a loaded question. How else would one guide thinking along a certain path? I appreciate your answer and "less tractible shorter projectile" is where I am going with this. The forces that work on a bullet to allow it to "nose over" the bow of the trajectory are considerable. The less tractible bullet resists these forces better and the long axis of the bullet does not change angle as the trajectory changes angle. I think we agree on this. Non Deforming Bullets: In an example where s/f is high, say 1.6 or higher, the resistance to change angle on the long axis increases greatly (I do not think that s/f is linear with the value, is it?). Any change of the angle would require a time component to effect. The higher the s/f, the more time will be required to change the angle. Impact yaw governs the length of the narrow channel. It is a complicated interaction but the salient points are that there are two significant factors. There is a time component and the yaw angle (angle of attack) at impact. The higher the yaw angle and the lower the s/f, the shorter the narrow channel becomes. The bullet tumbles at a shorter distance into the target. The smaller the yaw angle at impact and the higher the s/f at impact, the longer the narrow channel becomes. What say you thus far? | |||
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This is quite strange. These statements were made on this thread:
Now, on another thread, the same person says, about using a copper monometal of 175gr in a 9.25" twist: Yet the bullet in question has a stability factor that is more than 1.0 from a 9.25" twist and it delivers stable flight in air. He condones the use of a 180gr mono in a 12" twist 30-06, but not a 175gr mono in a 9.25" twist 7mm. The 175gr 7mm has a better s/f than the 180gr .30".  I suppose that, if you cannot make up your mind about the really fundemental things, this is to be expected.
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JWP475 I've no problem with anything Bryan stated. However, he does state "the window of proper stability is quite large" and that it is. It is within that window of stability that I am discusing. There are degrees of stability within that range. The point here is that the range of bullet weights within the rates of twist I mentioned are most likely to produce the highest BCs respective of the other twists. This is not to say those other twists do not "stabilize" those same bullets. It is simply to say a certain weight of bullet of a given caliber is best stabilized by a certain tist rate. It is a measureable fact. Larry Gibson Larry Gibson | |||
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Gerard, You are wrong again, you make too many assumptions and the wrong one's too. My comment about the 175 gr TSX relates to mono metals in a 7mm-08 that was actually designed to work with ligher bullets, hence the slower twist, and if this does not get the point across, the cartridge features a short throat and one does not want an overly long bullet to be seated too deep into the case, robbing it of powder capacity to reduce the velocity drastically, given its small cartridge case. The rifle was not designed with this in mind. Simple enough for you? Perhaps you should look at Alf's graphs published above, that SF actually increases down-range and, hence the incomprehensible specification that ... "With FN bullets we recommend a stability factor in EXCESS of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal." Also, I have never condoned shooting a 180 gr mono metal bullet in a.308 cal with a 1 in 12" twist. (You are making this up) Just about all gunwriters recommend an SF between 1.3 and 1.5 as a rule of thumb. I have refered to this in a previous posting - reason being to cater for various climate conditions and variations in twist being slightly off of what it is supposed to be. Please concentrate .... rule of thumb, not exact dogma, as you dogmatize - "With FN bullets we recommend a stability factor in EXCESS of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal." .284/175 Barnes-TSX BT, SF = 0.96 from 2,100 to 2,500 fps in a twist of 9.5" .308/180 Barnes-TSX BT, SF = 1.05 from 2,500 to 2,800 fps in a twist of 12.0" The above speaks for itself. Warrior | |||
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As usual you say I am wrong when I am not. You "say" all the time without presenting any proof or fact. We are used to that. However, here is some fact: Your calculation is wrong. Look at it carefully, fix it and then apologise. | |||
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Gerard, OK, here we go about my calculations being so incorrect and not instructive. I wrote Th Herring from Barnes Bullets and asked him the exact measurements per their drawings, and the specific gravity of the copper they use (8.96 instead of the standard published figure of 8.93 on which I based my calculations). As it turned out, their measurements also differ slightly from those I took from the Quickload program. Also, the .284/175 gr TSX only comes as a Solid Base and not as a BT, as listed in Quickload. So let us now see how it pans out using the figures from Barnes (and what we should remember as well, is that you knew all of these differences on the fly in a clairvoyant fashion, and as such, your calculation is the correct one, and by implication vastly different from mine): .284/175 Barnes-TSX S, SF = 0.98 from 2,100 to 2,300 fps in a twist of 9.5" .284/175 Barnes-TSX S, SF = 0.99 from 2,400 to 2,600 fps in a twist of 9.5" .308/180 Barnes-TSX BT, SF = 1.04 from 2,500 to 2,600 fps in a twist of 12.0" .308/180 Barnes-TSX BT, SF = 1.05 from 2,700 to 2,800 fps in a twist of 12.0" So it is as close as the breath of a hair of what I had previously (please put on the reading glasses) , without having exactly drawing measurements. There is no need for an apology whatsoever that you so assiduously seek. That was just part of your smokescreen to shift the argument to calculations, instead of the logic that I submitted that both scenarios is such that these bullets in question cannot be recommended for use in these twist rates. Over and out. Warrior It is the mark Of an Instructed Mind Not to seek exactness But to accept the degree of precision To which the nature of a subject Will admit. --- Aristotle --- | |||
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This is priceless.
All that trouble when all you needed to do was to pay attention to the thread right here. Let me give you a clue: From your post of 20 April above, you quote me as saying: "Yet the bullet in question has a stability factor that is more than 1.0 from a 9.25" twist..." But you do your calculations based on: ".284/175 Barnes-TSX BT, SF = 0.96 from 2,100 to 2,500 fps in a twist of 9.5"....." So I still say: Your calculation is wrong. Look at it carefully, fix it and then apologise.  No, not clairvoyant, from actual measurement of the bullets in question and a correct calculation, not a thumbsuck like you usually do.  You got that one right. The smokescreen card - dont you ever come up with anything original? Of course you can see now that you were being paranoid, as usual, instead of paying attention.  Logic???????!!!!!!!
I suppose this is your way of covering for the innumerable gaffes and mistakes you have made, including the one above. If ever a quotation was misplaced, this must be a prime example. A question for you: Do you also indulge in self flagellation? You seem to be a glutton for punishment by the way you keep returning with mistakes and pontificating up the wrong tree.  | |||
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Gerard, I am well aware of this, and I have not overlooked it. I based my calculation on the standard twist rate for a 7mm-08 Rem that is applicable. So that every one that owns a 7mm-08 Rem can take heed. Not all of them might have a twist of 9.25" and that is why I stated specifically 9.5" twist being the industry standard, and in terms of that I am correct. So, no apology. Incidently, does this now mean that you recommend that this guy shoots the 175 gr TSX bullet in his very own 7mm-08 with his twist of 9.25"? Perhaps you should look at Alf's graphs published above, that SF actually increases down-range and, hence the incomprehensible specification that ... "With FN bullets we recommend a stability factor in EXCESS of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal."
And let us not forget you fabricated the above false statement ... sucked it out of your thumb to bolster and agument against me that has no legs. These are the typical ploys you are useing. My unwavering position is still that the .284/175 gr TSX is not to be used in a 7mm-08 Rem and a .308/180 gr TSX is not to be used in a twist of 1 in 12". Writing to Ty at Barnes had the redeeming benefit of correcting some errors, as I have explained above, so one can update one's database. That was really no effort on my part, but rather fun. Warrior | |||
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Warrior, Truvelloshooter, Chris Bek (Pontificus Erroneus for short)
Wow, that is lame. Way too lame for such a big blunder. I stated that the sf of two bullets are similar. You said they are not - read the posts - and produced a calculation to prove me wrong. You messed up as usual and now you try to lie your way out of it. If your intention was to prove your point by way of "the industry standard", why did you not use 1:10" for the 180gr bullet? That is the CIP standard for a 30-06. But wait - there is more pontificating up the wrong tree!!
1:9.5" is only the CIP spec and fact is that there are more rifles that are not 9.5 than what are. From my database of twist rates, used by various manufacturers over time: 7mm-08 Remington - 1 in 9" - Thompson/Center Rifle 1 in 9.25 - Remington 770 (All current 7mm Cal Remington rifles have a 1:9.25" twist.) 1 in 9 1/2" - Browning 81, BLR, A-Bolt II; Sako; Savage (present); Tikka T3 1 in 10" - Remington 7, 788, 700; Winchester 70; Savage 110 You see, very few manufacturers follow the CIP spec when it comes to twist rates, it is not compulsory. You are wrong again, Pontificus Erroneus.
Apart from the fact that this question is a weak attempt to draw attention away from your blunder, you are the one who is confused about twist, stability and bullet length, not me. See below the series of statements you have made: "Bullets can be over-stabilized .... from say 1.0 (just stable in air) to let us assume 5.0. So a higher SF is not necessarily better." I see, just stable at more than 1.0 is ok. Higher stability factor is not required. ".308/180 Barnes-TSX BT, SF = 1.05 in a twist of 12.0" So your calculation shows that a 30 cal 180gr mono from a 12" twist is ok. "Once you have sufficient gyroscopic stability it becomes a moot excercise to increase the spin further." More than just stable (SF=1.0) is unneccesary and the TSX in your calculation above is good to go, despite the fact that we are discussing a 12" 30-06. "In practice, you want the SF value to be a little greater than 1.0 to allow a margin for error" Just more than 1.0, like the mono in your calculation, is fine - The 30 cal mono from a 1:12" twist. "I made a general point that additional twist was superfluous, once sufficient gyroscopic stability was achieved." Just as long as the SF is more than 1.0, the mono in your calculation will be ok. "My unwavering position is still that a .308/180 gr TSX is not to be used in a twist of 1 in 12". But it has a SF more than one?? So now a mono at just over SF=1.0 is not ok. "I have never condoned shooting a 180 gr mono metal bullet in a.308 cal with a 1 in 12" twist. (You are making this up)" Now a SF of just more than 1.0 cannot be condoned? What has changed - your mind? Did I make up what you said above? Do you read the drivel you write? | |||
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Gerard, All this dribble when you elect to ignore what I have said: Just about all gunwriters recommend an SF between 1.3 and 1.5 as a rule of thumb. I have refered to this in a previous posting - reason being to cater for various climate conditions and variations in twist being slightly off of what it is supposed to be. So again you are skewing what I have explained. I cannot recommend an SF of 1.05, AS IT IS MARGINALLY over 1.0. You must either be blind or it is just a willfull attempt to skew things. I am inclined to believe the latter. Even with a twist of 9.25", intead of 9.5", the SF is 1.04 from 2300 fps to 2900 fps. Still marginal with no adequate margin of safety, as explained at leat 3 times to you. But that is not all, I have given more reasons, apart from twist, why it is not ideal to shoot a 175 gr TSX bullet in a 7mm-08 Rem. If I can only get it into your skull, the 1.3 to 1.5 stability factor is a rule of thumb, it is not evangelical gospel or dogma like you propagate ... "With FN bullets we recommend a stability factor in EXCESS of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal." This is so minute, do the calcaulation and see the difference between an SF of 2.44 and 2.50 - this is heresy of the kind that only a Rasputin can preach !!!  Warrior | |||
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Pontifcus Erroneus,
Ok, let's explore this 1.3 to 1.5 thing you have read somewhere and have done no research on. You say that this is not a rule that is written in stone. Accepted. It is a guideline and it is flexible. Would you then say that a SF of 1.29 is too low and therefore not usable? Likewise, is a SF of 1.51 too high, or can we still use bullets at that level of SF? | |||
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Those reasons being what? Cant find where you said that. VVarrior | |||
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Gerard, Let us put the spotlight on your stability recommendation and illuminate why I find your view fascinating and at the same time intriguing: You recommend a SF value in excess of 2.5 for .375 FN Solid bullets, but when the diameter of the bullet drops to .366, this requirement somehow drops to a minimum SF value of 2.0; so it seems different rules apply for a 9,3 bullet as opposed to a.375 bullet. Intriguing, as I have not seen this phenomenon addressed in ballistic literature. With this kind of logic, one would expect then that when the diameter is dropped down further to .338 that the SF value could drop to say 1.5, or conversely, when the diameter increase from .375 to .416, or to .423, or to .458, or to .510, that we should actually see new break-points in the minimum SF value, as you argued at the time that stagnation pressure is diffent for each caliber. Somehow this is not being specified, or the theory has not yet been advanced that far, but we do have these definite break-points between the .366 and .375 calibers from you. A repeat of what I published before: "The strange thing is that we know from many PH reports that the .375/300 gr Rhino Solid, with an SF value of 2.06 at 2,500 fps is yielding reliable straight-line penetration. "In order to validate my figures, I have asked the owner of Rhino Bullets to measure the bullets for me, and based on what he gave me I have recalculated the SF values for their Solids. Just like the Barnes Solid, the Rhinos are also made from brass (SG = 8.4). The results are as follows: Cal/Bullet --- Twist -- SF ----- MV 9,3/286 gr -- 14.0" -- 1.39 -- 2,300 fps .375/300 gr - 12.0" -- 2.06 -- 2,500 fps If the field results were plagued with failures, these Rhino bullets would not sell, but the truth is the PH's are ordering them again.” And likewise, I am sure Barnes would not put their .375/300 gr Solid FN bullet out there if it does not work, i.e. it does not attain this magic requirement level of 2.5. Let me quote what I wrote you some time ago … “Remember how you lied to me about the SF value of the .375/300 Barnes Solid of having a greater SF value than 3.0 .... and my continual request to recalculate it ... this was my question to you after umpteen times ... "Still no answer on how you wanted to cheat me with the .375/300 gr Barnes Solid." It is very similar to the Rhino at around 2.06 but you insisted my program was old and all that shit. The fact remains it is way under 2.5 (the magic Rubicon-line).” But then Gerard you go further and you recommend only a minimum SF value of 1.4 when we get to your HV bullets, with no different break-points for different calibers - interesting. So, apparently somehow different gyroscopic rules apply for HV bullets as opposed to FN bullets. The logic of this has not been fully explained by you, and my guess would be that you would wiggle out of it by saying it is a trade secret (new discovery) and so, that not even the mathematicians will be able to unravel it. Truth is it would be difficult to get these HV’s also up to in excess of 2.5 – for example, check/model it with the .366/230 gr HV bullet in a standard twist of 14.2 and see what you get” This is what you posted on August 2005: “GSC recommends choosing an HV that will result in a stability factor of at least 1.4 for hunting inside 500m. The 375300HV needs 1:13" twist for stable flight. In a 1:12" it needs 3300fps to achieve a stability factor of 1.5 and the SF will drop to 1.38 at 2000fps which is not ideal. From a 1:12" twist, the 265gr HV will deliver more reliable terminal ballistics.” We do know though that your .375/300 gr bullet do provide straight line penetration in a twist of 12” as tested by RIP. The SF of 1.38 @ 2000 fps is a non event. We now know that SF increases downrange and it cannot be calculated by the WinGyro program – its values for SF’s is in terms of launched velocities and not striking velocities downrange. So the apparent shortfall of .02 (1.38 vs 1.40) is a misinterpretation of what actually happens. To answer the question, is a SF=1.38 adequate at launch - the answer is yes! Reason being, the safety margin is well above the 1.0 mark and the SF increases further downrange. Warrior | |||
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Hey Warrior, Do you shoot crows? VVarrior | |||
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Pontifcus Erroneus, Why write 788 words to sidestep a simple question? Listening to the little voices in your head again? Here, let me help you. I will repeat them for you. "Would you then say that a SF of 1.29 is too low and therefore not usable? Likewise, is a SF of 1.51 too high, or can we still use bullets at that level of SF?" Now, let's have some fun with your 788 words.
While you nevertheless do not understand a word of what is going on. Allow me to illustrate the point.
Why would you think that stability factor has something to do with the diameter? You really do not understand the principles involved and I know why. When you are asked simple questions like the ones I asked above, you ignore them and just rehash old stuff, where you were proved wrong anyway. Repetition does not make something the truth, you know.
Well, that is easy to explain. You do not read the right things and that which you do read, you do not comprehend. Simple.
Your logic (the kind that does not work all that well), not mine.
You need to pay attention here: It has nothing to do with diameter. Clue: If someone said "That red Ferrari is faster than this blue Toyota Corolla." It is probably because the Ferrari has a 400Kw 12 cylinder engine and not because it is red.
Nope, I never argued that, you are confused again. But, in any case, it has nothing to do with diameter. Come on, stay with it here. You can work this out. Keep going, do not give up. It has only been six or seven years. Sooner or later the little bulb over your head will light up.
Many tables, dealing with how stagnation pressure varies, have been published and air/fluid flow literature is rife with it. You mean you have not noticed? I truly dispair of your ability to read and comprehend.
Would this be like the ones referred to in the third paragraph from the bottom?
Yes, it brings back fond memories because you stumbled into such a monumental blunder when you believed it. A man with a white stick could have seen you are being led by the nose, but you were entirely too thick to catch on. You spent what, three weeks writing to Ty and getting into all sorts of contortions, when what I stated was clearly impossible. How could a brass solid of the same weight and caliber as a copper one have a higher SF at the same speed? Goodness, that was funny. Four years ago and you are still hurting about it - priceless!! It does prove that you have learned nothing in four years though.
Yes and the SP range is different from the HV and FN range. This is common knowledge and an idea that has been around since the rocks were soft. I can assure you I did not discover this.
That comprehension disability thing that you suffer from again. It is not up to me to explain something that has been very comprehensively covered by many researchers for several decades. Just because you discovered tractibilty last week, it does not mean that it is new to us.
Wow! The extent of your ignorance is truly staggering. I find it difficult to believe that you think one SF fits all. Bullets are not like sleeping bags, you know.
Actually there are some that get way beyond that. Imagine this one in a CZ550 with a 1:9" twist! This one is an amazing plains game bullet out to 400m in any standard 375H&H with its 1:12" twist. I thought my "pissant amateur" comment to you was a bit harsh but I see it is justified after all.
I don't have to. It was done when the bullet was designed years ago and it is here for all to see. Imagine this one in one of the 1:9" CZ550s!! It will probably be about SF 4 - stunning!!
And in the four years since then I have learned more new things about bullets and ballistics than I did making bullets in the 16 years before that. You, on the other hand, are still stuck in the 19th century. But there is much more of the same here. Go to any category of bullet, click on any bullet number and have yourself an aneurism, courtesy of the GSC specification data. 
No, we dont. RIP's test medium does not promote tumbling like an animal carcass does. That is what our FNs are designed for. Shooting animals. You see, this is your problem. You have no ideas of your own and interpret the results of others as you see it. Through a glass, darkly.
No, no, no!! The questions were: "Would you then say that a SF of 1.29 is too low and therefore not usable? Likewise, is a SF of 1.51 too high, or can we still use bullets at that level of SF?" Do not, I repeat, do not listen to the little voices in your head. Answer the questions in red above, not the ones you make up. Come on, concentrate!! | |||
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Wow, what a crap answer. Read my previous post, it says all. Warrior | |||
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Gerard, Do not throw the above on me, I definately do not think so. What a deception !!! You differentiated between calibers - .375 vs 9,3. You also offered stagnation pressure as the reason for the difference in required SF between these 2 calibers. Initially you claimed a a SF value in excess of 2.5 for your FN bullets, and when I proved to you that the 9,3/270 gr FN bullet provides straightline penetration, you quickly qualified that it was only so for the .375 caliber, and accepted that the 9,3 bullet do in fact provide straight-line penetration. The following extracts might refresh your memory. Chris: ... "Is the SF value of the 9,3/270gr FN bullet really in EXCESS of 2.5 ???" Gerard, .. "No it is not. It is a hair over 2 at 2.04 at 1200fps to 2.09 at 2600fps." Gerard: .. "Predictably you are going claim I contradict myself because I said the .375 bullet should be in excess of 2.5. It has to do with stagnation pressure that rises as the square of velocity and the fact that a 375H&H will get up to 2900fps with HV and FN bullets and a 378 Weatherby, and some others, will get a 300gr HV or FN bullet on the high side of 3000fps with ease. Now I am done educating you about bullet design." Chris: ... "Gerard thanks for divulging the SF value of the 270 gr FN bullet to me finally - it was like pulling teeth. 2.09 does not meet your design objective of 2.5, but I personnally never thought it would be a problem - only you class it as a problem by your very own writings. If it is a problem, then the bullet should be withdrawn from the market place if you want to be ethical about it. Or you may wish to simply drop your guestimate of 2.5 down to 2.0 and everything is then hunky-dory again and you could still sell the bullet." And this whole debate was triggered by your statement ... "With FN bullets we recommend a stability factor in excess of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal." This minicule difference ... yes, this is how fine you cut it.  Now this is incomprehensible !!! And it still has not been explained in a plausible manner, not so? Warrior | |||
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Hey Warrior, Do you shoot crows? VVarrior | |||
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Berger Bullets is listing optimal accuracy for 168 gr - 175 gr. match bullets in 1:12" barrels for .308 Win. My range data seems to bear this out. | |||
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Hey Warrior,
I think that Gerard is trying to tell you that caliber (diameter) is red and and stagnation pressure is Kw. Do you shoot crows yourself or do you have someone else shoot them for you? VVarrior | |||
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VVarrior, You are wasting your time asking him questions. He follows the SA communist trade union policy of demanding only and sidestepping anything that does not fit the Agenda they follow. Pontifcus Erroneus, So many mistakes, so much ignorance, so many lies, so little time. What a flip flop! You mentioned it three times and now you deny it. What a croc!
Red Ferrari / Blue Toyota. Here are some clues - try to work it out: Is the big difference between a 375H&H and a 9.3x62 the diameter or the speed? Is stagnation pressure primarily a function of bullet speed or bullet diameter? Does stagnation pressure have an influence on overturning moment? Does SF have an influence on overturning moment? I will not hold my breath while you wrestle with these concepts. If you have not been able to figure it out over the last four years, since you first raised the subject in 2005, I doubt that you are capable of doing so in the foreseeable future. Goodness knows it has been explained enough times now. Its tough when you have to resort to lies to try and bolster a weak argument. Here is the question I was asked by Dan in 2005 and my answer. ---------------- "Gerard, In the .375 H&H, what twist would be needed to stabilize the 300gr HV and 300gr FN bullets?" ---------------- "500grains, Standard 375 twist is 1:12". GSC recommends choosing an HV that will result in a stability factor of at least 1.4 for hunting inside 500m. The 375300HV needs 1:13" twist for stable flight. In a 1:12" it needs 3300fps to achieve a stability factor of 1.5 and the SF will drop to 1.38 at 2000fps which is not ideal. From a 1:12" twist, the 265gr HV will deliver more reliable terminal ballistics. With FN bullets we recommend a stability factor in excess of 2.5 for reliable linear penetration. The 300gr FN has a stability factor of 2.39 to 2.44 from 2000fps to 3000fps. Again not ideal. Stable flight requires a twist of 1:18" but will result in a bullet that tumbles on impact as surely as the sun will rise tomorrow. The 375270FN is best for linear penetration in a 1:12" twist." ----------------- So, which part of my answer, recommending a SF of 2.5 with FNs for the 375H&H, do you not understand? All of it, it seems.
I designed the 9.3mm FN. Part of the design process on paper was the calculation of SF, CG, correct nose and shank lengths, nose angle, meplat size and a number of other criteria for a range of prototypes. Then came the drawings, the cnc programming and the production of the prototypes. I did extensive range tests with them on a number of different media. After that and before release to the market, I field tested them on large animals and two PHs did comparative field tests on a number of buff, hippo and giraffe. The final choice was made and the 270gr FN went to production. This was in 1997/8. Do you really think you could prove anything to me about this bullet in 2005, after it had been in use successfully for seven years? Your arrogance is only exceeded by your sheer stupidity.  As a matter of interest, the 270gr 9.3mm FN is no more. It has been further refined and improved for better linear and deeper penetration. It now weighs 260gr. Your extracts from the discussion in 2005 are interesting. It proves that you have not come to grips with the success of our FN range of solids. It is a zero failure record - possibly the best in the industry. It is sticking in your craw for some reason. For four years you have been trotting out the fact that you do not buy the SF requirements for our various caliber and weight FN solids. You are like a stuck record. It has not sunk in that the zero failure rate of the FN range might just be because I have placed a specification limit on certain criteria. Did you not say that most gunwriters recommend a SF between 1.3 and 1.5 for hunting? Why do you not answer the question I have asked several times now? Can we or can't we use bullets with a SF of 1.29 and 1.51? The hackneyed debate from 2005 - And the 300gr FN bullet you quote is what caliber? A 375H&H I see. And I recommend a minimum SF of 2.5 for which caliber FN? 375H&H I see. SF minimum 2.5 for a 375 H&H. It is said that even the most stupid will remember something if it is repeated seven times. You prove that theory wrong. You are also the only person questioning the GSC specification when, in fact a number of other bullet makers have similar specs. Yet, GSC is the only bullet manufacturer that you attack constantly. When you write to or call other manufacturers, you accept what they say as gospel. You do not question the opinion of other manufacturers. They can come up with with any half baked opinion and you will accept it as fact. Even when it is as clear as the nose on your face that they have no clue what they are talking about, their opinion is somehow valid. When you question what GSC does and I reply in good faith, you find that it is unfounded for some reason and resort to foul language and insult. This despite the fact that GSC is responsible for changing the face of bullet design in several significant ways and has an excellent record of reliability and success. You need help, you are a sick puppy. Yes, at GSC we have a rigid set of specifications. Other manufacturers often do not comply with the spec we set. They have their own criteria. If your fave bullet maker has a diferent set of specifications to ours, why question our spec? When your fave manufacturer produces wildly differing bullet lengths, weights and shapes within the same batch, that is no problem. I do not see you taking them to task for not coming up to scratch and I do not see you railing at them constantly, for years on end, to improve their reliability, accuracy and consistency spec. You have no problem with manufacturers who make patently absurd claims on their websites. Claims that are contrary to what Alf and many others know are fact. You constantly harrass GSC to lower their spec. Why do you not apply the same rabid zeal to raise the spec of some other manufacturers? We have the most rigid and most dificult to maintain specification in the industry and we will not lower that spec to meet your or your fave bullet maker's lower standard. Get used to it. So I ask again: According to your statement SF 1.3 to 1.5 - Can we use bullets at 1.29 and 1.51 or not?
It has been explained to distraction. Over and over and over. Everybody is tired of it. But, time after time you come up with your stuck record idiot opinions, making disparaging statements about GSC products, asking the same questions and making the same old statements. Every time you are proven wrong, caught out in lies and shown to be a poseur. I do not think you have had an original thought in the last ten years. You are not interested in interacting by considering other opinion or answering questions asked of you. You only put forward your antiquated pet theory and everything else is bullshit or horseshit or Googled. Most of what you Google, you don't understand anyway. We have seen a lot of that. What qualifies you to be the only one demanding answers? What qualifies you to tell me that GSC designs do not work the way I say they do? How many sucessful bullets have you designed/produced? One/nil? My tally is more than 250 designs and several million produced. How many animals have you shot and seen shot? 20? 40? 100? When you can lay claim to a couple of thousand, I might take you seriously. You remain a pissant amateur. So: According to your statement of SF 1.3 to 1.5 - Can we use bullets at 1.29 and 1.51 or not? Your lack of an answer to such a basic question shows that you are not sure what the answer is. This question has not been asked before and you have nowhere to Google for it. You are stuck!! | |||
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Gerard, I will make it short and sweet - I do not believe for one minute that a .375 bullet launched at a stability factor of 2.44 is a NO GO situation and that it is prone to unreliable linear penetration. Also, I do not buy the postulate that a .366 bullet needs a stability factor of 2.0 to perform reliably, and that one needs in excess of 2.5 simply because the .375 bullet is shot faster by 200/250 fps. The FN bullet is as fine as can be, that is not my argument nor an attack, I differ with the postulate. How come the the 9,3/286 gr Rhino Solid bullet works splendidly with: .366/286 gr-- 14.0" -- 1.39 -- 2,300 fps .375/300 gr - 12.0" -- 2.06 -- 2,500 fps The one is lower than the magic 2.0 level and the other one below the magic level of 2.5. That is proof enough for me, especially when we consider that the Rhino's meplat is smaller and not as sharply flat. That is why I question the theory. A bullet's gyroscopic stability in air is negated by the target density (a thousand fould more) and the pressure it encounters. Therefore the twist rate has no real effect on the stability of the bullet in-target. The geometry of the bullet takes over - the new factors for reliable straight-line penetration becomes the position of the COG, the length of the bullet and the size of the flat meplat to provide shoulder stabilization. All work together to negate the overturning moment. And as for throwing mud, you are the king and as guilty as hell !!! Warrior | |||
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Alf I agree with you and thanks for your detailed response. The clincher is this whole debate for me is ... A bullet's gyroscopic stability in air is negated by the target density (a thousand fould more) and the pressure it encounters. Therefore the twist rate has no real effect on the stability of the bullet in-target. The geometry of the bullet takes over - the new factors for reliable straight-line penetration becomes the position of the COG, the length of the bullet and the size of the flat meplat to provide shoulder stabilization. All work together to negate the overturning moment. Now if we look at the GSC-FN bullet we see all the ingredients, regardgless of a higher twist than necessary, present for straight-line penetration: 1) Shorter than most other solids 2) A larger FN meplat, not ogived as a typical RN, than most others So the geometry of the bullet works together to negate the overturning moment, not the twist. In-target the angular velocity is lost very fast, so we cannot hang our hats on that. Imagine the in-target angular velocity of the bullet every 6 inches, up to when its stops. Any imperfections with the barrel will just be exacerbated by a faster twist (and the bullet). I am not trying to compare bullets, but explore the underlying theory. As always, I appreciate your explanations as you take it back to first principles. Warrior | |||
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Alf, Agreed. Warrior | |||
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I would still like to know where you get your crows. VVarrior | |||
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Pontificus Erroneus,
1. I do not care what you think - Your thoughts and opinions carry no weight whatsoever as they are based on misconceptions and an addled logic that is probably unique to you alone. 2. The statement above is a distortion of the truth (a lie) as I have not said that. Only you could come up with not believeing something that was not said.
1. See my item (1) above. 2. Because you do not know enough about the subject and you are not willing to learn. What do you want GSC to do? Cow-tow to your ignorance by discontinuing the high SF bullets? What? see (1) above. Ask them yourself. You have direct access to the designer and management level there, not so? That reminds me: The question you have been unable to Google - According to your statement of SF 1.3 to 1.5 - Can we use bullets at 1.29 and 1.51 or not? So they have a number of specifications that differ from our FNs. What are you suggesting? Must we make our FNs the same shape as the Rhino solid or are you going to pester them incessantly until they change their shape to be the same as ours? While you are at it, our FNs are made from copper and the Rhino solids are made from brass. Should one of us change and who are you going to badger about that for the next ten years? Tell us something we do not know. You do like repeating things and to pretend that a new question or position is posed. Why do you repeat the obvious? What is the purpose? These are all facts that were discussed and agreed upon long before you made your sorry appearance on this forum. You sure are thick as two bricks. Have you not noticed that you always get at least one chance before I react to your idiotic statements? I react by pointing out your lies, deceptions, bad logic and lack of a grip on the subject you pontificate on. If you want to call it mud, guess what: Item (1.) applies. | |||
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I have also seen this claim by some that a faster twist will yield deeper penetration. Here is what Gerard says and he seems to be belong to that school of thought as well and I quote:
Let me repeat, I do not buy the postulate that a .366 bullet needs a stability factor of 2.0 to perform reliably, and that one needs in excess of 2.5 simply because the .375 bullet is shot faster by 200/250 fps. This has not been explained properly nor backed by scientific principles. Also observing these break-points with the naked eye in the field is an amazing one to me, going from SF=2 to SF=2.5 !!! Furthermore the explantion advanced by Gerard that ... the higher the stagnation pressure the more SF that is needed between a 9,3 and a 375 H&H is still a mystery to me. Stagnation pressure cannot be linked to SF values. Gerard has till today not validated his claim of how SF as a numeric value, based on the density of air, affects straight-line penetration in flesh. The problem that we run into if we accept Gerard's explanation that we need a higher SF for the .375 bullet based on the increased velocity of the 375 H&H over the 9,3x62, then it should follow that the SF number should even be higher for the faster 378 Wby Mag. Even more precise ... that the 300 gr GS-FN bullet is not ideal in a 375 H&H, as its SF is equal to 2.44 and not 2.5 !!! That is when things break down for me, if one can actually see it with the naked eye in field tests. That is amazing. Warrior | |||
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 About those crows. What do you shoot them with? VVarrior | |||
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Warrior, Hate to break the news to you, but Gerard argues that the 300gr GSC FN is NOT ideal in the 375H&H. And he argues that consistently and constantly, at every opprtunity. He argues that the 300 is not ideal for the very same reason, insufficient SF value, which you are now attacking him for not arguing. JPK Free 500grains | |||
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Alf, The motion and behaviour of a bullet has been researched, documented, theorised about and discussed for more than a century. From the moment the firing pin contacts the primer, to the point where the bullet is motionless at the end of its flight path. Every aspect has been analysed: How the bullet leaves the case and transitions through the various stages through the freebore, to fully engraved, to the moment it uncorks from the muzzle. The incredibly small fraction of time as the bullet emerges from the muzzle and clears it has been scrutinised in detail. Every dimensional change it undergoes, every vibration it imparts to the system and every anomaly that occurs in internal ballistics has been documented and discussed. External ballistics has also been similarly scrutinised. Flying through the cloud ahead of the crown - what happens on the way to the target, be it a target at 5m or a target at 5000m. Doppler radar has been employed, spark photography ranges have been built to capture the image of the flying bullet and the most incredibly intricate studies have been done, to establish what influences the flight of the bullet. Supersonic flight, subsonic flight and every manner of variable and transition has been minutely examined. Time has been reduced to nanoseconds in some of these investigations. Terminal ballistics and the investigation and discussion thereof, has been around since most of us can remember. Research and discussion span from the most learned and detailed research by a number of the very greatest minds we have known, all the way to Chris Bekker's opinions. There is nary a detail that has not been covered. In some instances the same detail is covered over and over and over and.......  But there is a huge gap in our knowledge about which I find little detail: The fraction of time it takes, from the point where the nose of the bullet contacts the impact medium, to the point where it is fully immersed in the impact medium. Do we accept that the bullet just "arrives" and that the manner and attitude in which it arrives plays no role? Do we assume that, as long as it is within a certain range of manners and attitudes, it will act in about the same manner with similar results? Do we accept that the way the bullet "does its stuff" is in the hands of the hunting gods? I do not think so and the little bit that we do know suggests otherwise. You have quoted research that ties the shape of the bullet path to the angle of attack at impact. We know what shapes and materials are good for penetration in tissue and what works when we have to deal with tank armour or the rocks of one of the moons orbiting Saturn. But there is this fraction of time, when a hunting bullet transitions from air to impact medium, about which not much is said and done, because the people to whom this is important do not have pockets that are deep enough. I have spent my pocket depth over a number of years to take a look at this transition. Lacking a portable spark photography range and tame game that will stand still while pictures are taken while they are killed, I had to find simpler methods of determining what influences this transition from flight to denser medium. What I found was first translated into a general feeling/opinion, then solidified into a guide line and eventually became a design specification that I found that works. Pontificus Erroneus automatically assumes that I have powers of observation that transcend the superhuman. He scoffs at the ability he ascribes me to observe angles of attack at 2000fps, that are measured in minutes and seconds. He ridicules the assumption he makes that I can tell the difference between the overturning moment of a bullet at SF 2.44 and 2.5. 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. In the case of Pontificus Erroneus, the toes of the foot in his mouth may also be used. Do this enough times in a year and over a large enough number of years and it brings one to a point where you can observe a trend. It is then easy to determine safe cut off points that allow a margin of error. This results in a specification based on field results and which can be tied to known parameters of ballistics and manufacturing. We know that a bullet will probably start tumbling in flight, when conditions approach a SF of one so we say that a safe SF condition is 1.1 or higher. We know that a particular tractability condition is required for a particular flight behaviour at a particular distance, so we design accordingly. We know where to place the center of gravity of a bullet so that it transitions well from supersonic flight to subsonic flight. In all instances there exists a condition where a desired/undesired result is assured, a condition where that result is probable and a condition where that result can usually be avoided. We learn where safe limits are and we set and write a specification. Until someone comes along with a better explanation than SF for what has been observed, that is what I will use as a specification parameter for the relationship between twist, caliber, bullet shape and intended use. With the above in mind, I refer to what I said two pages back. Pontificus Erroneus, Have you Googled the answer to my question yet or are you still stuck? | |||
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Gerard, The discussion here is about the very same bullets with the very same set of attributes, save for the twist rate (ie SF value being imparted) and how you can tell with the naked eye that your 9,3 FN bullet needs a minimum SF value of 2.0, whilst your .375 FN bullet needs in excess of 2.5 on the basis that you advance that the the 375 H%H is about 200/250 fps faster. This comes off your website ... "A stability factor (s/f) greater than 2.0 is required. A s/f of 2.5 is desirable for faster calibers." We then need to explain the difference why the SF should be only be 1.4 for say a 9,3/230 gr HV bullet, but we need a minimum SF of 2.0 when we come to the FN version (260 gr FN). Quite significant to note is that no distinction is made with HV bullets between the 9,3 and .375 bullet - both can fly with a minimum of 1.4 SF value, unlike in FN form. This needs clarification. Then it needs to be explained how different stagnation pressure is responsible for the different specifications that are advanced. Then link stagnation pressure with SF values and straight-line penetration to support your view - see http://en.wikipedia.org/wiki/Stagnation_pressure All we need from you is an eloquent explanation as to the first principles of your postulate and not your rantings like an angry chimp. Warrior | |||
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Truly, you are dumber than a bag of rocks. First you dont believe something I did not say, then you ask a question after quoting the answer. You demand incessantly from a position of zero knowledge, but never so much as acknowledge questions asked of you. Answer some questions yourself, pissant amateur.
Do you read the drivel you post? A quick calculation shows that a 3230gr 9.3 bullet will be about 15" long and need a twist of tighter than 1:1". I will leave listing the difficulties of such a thing to you. No doubt you can think of many more, real and imaginary, than I could. | |||
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