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One Of Us |
I've received several emails in the past few days asking what HEYM's twist rate is in a .470. Below is a CIP spec sheet for the 470 NE.  Every detail of the cartridge's min and max measurements, chamber, pressure, bore dia., lands, grooves, rate of twist, etc... are all defined by CIP - typically in conjunction with gun makers, proof houses, historic records, original cartridge specs, etc... All manufacturers in CIP countries must build their rifles (and ammo) in accordance with these strict specifications, i.e.: variations in rates of twist are not allowed. If they don't, they will not be "legal," won't pass proof, and can not be sold. So the answer to the twist rate in the 470 is one turn in 533mm, as highlighted above or 1:20.9842". If your 470 was made by Holland & Holland in England or HEYM in Germany, or Fanzoj in Austria, or Piotti in Italy, etc... it has the same rate of twist and adheres to the same specifications as noted in the sheet above. Hope that helps some readers. | ||
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Good stuff. At least some benefit of Standardization. I would like to know what the sequence was re the 404 Jeff as I BELIEVE RWS changed the cartridge dimensions slightly a few year ago. Not that the 404J was totally standardised beforehand as I have seen quite a few different chambers. Can you shed any light on this ? | |||
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Hello, Nigel. I am not familiar with any dimensional change history of the 404, but I can tell you that errors have been found in the original CIP measurments (when they were first standardized by CIP), and subsequent changes have been made as popularity - or complete resurection - of a particular cartidge comes to light. The 450/400 3" is a recent example of this with the angled vs. radiused shoulder issue that was identified in 2007 and had to be changed before they would proof any new 450/400 3" rifles for us. (They insisted that we make the chambers to the original 1923 specifications, and we did.) The CIP sheet on the 404 notes a 1984 date (when it was standardized) and a 2002 date for revisions. It does not note what those revisions were in 2002, but it is certainly possible that RWS led a change, as it was Triebel that led the 400 change. Maybe someone else here knows more about the 404's history? | |||
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Chris, I checked my Krieghoff 470 Nitro with a jag and patch and came out with 1 in 20. To make certain it was accurate I called the Krieghoff center in PA. They told my 1 in 480mm or 1 in 18.9. Do you know if Kreighoff does not follow CIP or did the Service Center give me bad inforamtion? Thanks for your original post. | |||
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FWIW I just hung up the phone with the Kreighoff service center in PA. He guaranteed the twist rate of the 470 K-Gun is 1 in 18.9. Chris I saw your PM after this post, thanks. | |||
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Chris, my 1908 450-400 has a distinctly radiused shoulder. Looks like a fat weatherby! My fireformed rounds won't chamber in a Ruger #1. Not a big deal since I have custom dies, but am curious if the 'official' spec is tapered or radiused. Bob | |||
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That is the correct "1923" shoulder.
You are correct there too. The original spec had a double radius shoulder. When it was "standardized" by CIP, those radiuses or radii were interpreted as angles, and that was the CIP spec. It was unchanged until 2007 (presumably because no rifles or very, very few rifles were actually being built in the caliber.) When we ordered chamber reamers to make the first rifles, it was brought to our attention that the current spec was incorrect (the one with the angled shoulder)... months of back-and-forth ensued with the final result being a change back to the double radius shoulder. There are no proof laws in the US, so I suspect the Ruger chamber (SAAMI) is a version of the angled shoulder version. I do know that factory Hornady ammo will fit into either a Ruger (SAAMI) or CIP chamber. | |||
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That sounds about right for the 404 and what I had heard, just didn't know the sequence. Thanks for the info, much appreciated. Re the Ruger dimensions, since all guns into Europe have to be proofed before sale, how do they go if they don't follow CIP ? | |||
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The reason for the inquiries can be found in the 470 Bullet performance thread. The FN coolaid drinkers will flip when they discover that a 500gr copper FN bullet is supposed to need more twist to perform as well as it does. A conundrum. JPK  Free 500grains | |||
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Even on a thread without controversy you cannot resist taking a cheap shot, really shows some class. | |||
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There is no cheap shot in my previous post. And there is no controversy in the other thread either, there is only valid prediction based on rellavent testing and results in game and error from false hypothesis and inferences drawn from irrelevent "testing" which cannot accurately predict the performance of a solid in game and cannot repeat results achieved in real game. You may think there is controversy, but you are as mistaken. Tell me that inquiries about 470 twist are not related to GSC's web site's advised twist rate and the thread on 470 bullet performance. You cannot. Further, the GSC web site advises a substantially faster twist than the standard CIP twist for the 470NE, does it not? This represents a conundrum for the FN coolaid drinkers since the substantially shorter Woodleigh 500 grainers face no such limitation. (Though their performance would also be enhanced with a faster twist rate.) And a second conundrum in that the 500gr truncated cone copper bullets' performance defies the prediction that they will perform poorly because of the slow twist. 500gr NF's will perform well in your 470 at the standard or 1:18" twist, with the caveat that they will have the stengths and weaknesses of the truncated cone copper FN's. In addition, they will have an increased probability for veering or tumbling. But that probability is low to begin with and the added probability is not too material. JPK Free 500grains | |||
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JPK, Why do you miss the boat so much? The twist rate is charted for optimum stability, of which every bullet could use a little, but not necessary. Don't try and find a "conundrum" here, it doesn't exist. If someone finds a faster twist to be better, so that is fact, and it's a good thing for both RN's and FN's, but it is regardless of design flaw; ironically the very point in which you miss and have yet to address or understand. Stop this miss-direction, and let's try and keep this where it belongs. Yes, that was a cheap shot. No one brought it up until you did, and you know you should have left it where it was. Controversy there is my friend! And predictions based on testing is just that, controversial. Say what you like. Us that vote in favor of the FN's have VASTLY more DG experience then you, VASTLY more testing (which still boggles my mind how this concept eludes you) then you have ever even dreamed of. Now to say it's false hypothesis and inference is down right disrespectful and foolish, and requires you have proof otherwise. Not your word or minute DG experience, but you are going against volumes of experience and knowledge of which you haven't the slightest clue about. If you want to disprove theory, you must have substantial science and data to prove otherwise, which you don't have. Back off. Yes, 470 twist rates are relevent, but you still have to throw in that cheap shot. Why? GSC's twist rates are a good pool of knowledge to learn from, something you are not familiar with doing. It's good to play is safe when there is probability of failure, especially when it comes to someones life. You have no point! And the GSC 500 FN's will work in a 22 twist, so you have missed the boat again. Please check the chart again. I like coolaid, and it had nothing to do with bullets. The Woodleigh is not substantially shorter, and that has little to do with it's improper design. If this were true, it would prove so in testing! I NEVER has! Not once, not in any senario, in any media, ever, so let it go already. A faster twist will not fix the poor design, and I would argue it would even be noticable. No conundrum, except for you. The copper FN's do not defy prediction, you cannot read very well. If they do, as you say, taking your word for it, then it is because the FN shoulder stabilizes and (with GS Custom bullets) begins to expand slightly, broadening the meplat and increasing stability, just like I said. You must have not read all that I wrote you before. No conundrum, except yours. What probability? Where are you getting this? You quote data, as if you have some. Is it from your testing? Well, then game animals, as you say, are not predictable, so your "testing" is invalid...by your own words. You are going off chance at best, and we FN users have more "chance" then you do anyways. Just let it go... -Extremist "Pain is weakness leaving the body" -Instructor Victory in life is dying for what you were born to do. "I hope you live forever" -300 "Never judge an enemy by his words, he might turn out to be a better shot then a writer" http://www.gscustomusa.com | |||
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Even IF twist rate and bullet performance is tied together, Can we take the "bullet design shit fight" back to the other thread where it belongs and keep this one for discussion good information on Twists, CIP, SAAMI etc etc. I'm not adverse to a good, healthy, heated debate on forums but No need to screw this thread up. | |||
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In partial accord with 500N's request, I will limit this response. You miss the point. Twist rate is FIXED in every rifle of any description manufactured in Europe. CIP membership, which is ubiquitous there, requires the specific twist rate specified. Woodleigh RN's are proven, in real tests and in real results. But it is true that they are poor choices for slaying wet paper. The increased probability of the 500gr 470 FN tumbling or veering is from Gerard and based on his experiments and data. If you take the time to read his prior posts you would find the data and his discussions regarding twist, transition and veering yourself. JPK Free 500grains | |||
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New Guy Sadly no, Rifle makers are not bound to CIP...Only the ammo makers. Krieghoff, H&H and Purdey all use 1:16 twist for the .375. CZ use the british chamber dimentions for their .505 Gibbs Which are vastly different to CIP. So different from CIP in fact that original Kynock .505 Gibbs ammo will not chamber in a .505 CIP chamber!!! Same actually applies to .416 Rigby! The basic facts are...the British stopped making ammo a year before CIP was formed. CIP 'standardised' British rounds at what they thought was best - not what actually was. They are changing slowly... eg in 2002 they finaly chnged the barrel dimentions for the .404...they had specified the German 10,75x68 Barrel size (.421) and not .423 as every single barrel maker uses... Not sure what is going to happen with the .505 Gibbs... | |||
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Good to hear that they are changing things to how they should be !!! 505 Gibbs / 416 Rigby - why CIP didn't stick with the factory specs, no one knows. At least they are willing to change. The drawings were available for all the cartridges as Woodleigh has copies of most of them from when they started making bullets. Good to see they have changed the 404 to .423. | |||
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500...you can ask Geoff about that...many of his bullets made to original specs wouldn't fit in the CIP specified short throats...For the Norma PH line he has had to move cannelure possitions and even re-design the final shape on some like the .505 to get around the problem. Biggest problem is that CIP is overseen by the French with German technical input...and the Brits have basically refused to co-operate with them...so the changes are comming through the back door of real rifle makers in Europe pushing for change. | |||
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I would suspect anything that GSC says, as they are usually trying to shout down any and all competition, differing points of view, or anything else they probably judge as affecting their profit. There are bunches of bullets out there in the marketplace, and better ones in my opinion. He can keep his. ------------------------------- Will Stewart / Once you've been amongst them, there is no such thing as too much gun. --------------------------------------- and, God Bless John Wayne. NRA Benefactor Member, GOA, N.A.G.R. _________________________ "Elephant and Elephant Guns" $99 shipped “Hunting Africa's Dangerous Game" $20 shipped. red.dirt.elephant@gmail.com _________________________ Hoping to wind up where elephant hunters go. | |||
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But good God, C.I.P. is always shown such great reverence by so many on AR. Does this mean the European gods do not know what the f**k they are doing? Please say it ain't so. It just about makes me puke. ------------------------------- Will Stewart / Once you've been amongst them, there is no such thing as too much gun. --------------------------------------- and, God Bless John Wayne. NRA Benefactor Member, GOA, N.A.G.R. _________________________ "Elephant and Elephant Guns" $99 shipped “Hunting Africa's Dangerous Game" $20 shipped. red.dirt.elephant@gmail.com _________________________ Hoping to wind up where elephant hunters go. | |||
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Will...definition of hell - German sence of Humor, french flair for tecnicalities, english flair for cooking, Finnish communication, Russian compassion....and anglo/ french co-operation | |||
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I would never have thought so, he so helpful and complimentary of others, it is just that he forgets to take his pills sometimes.  Warrior | |||
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The CIP twist spec for a 470NE is 1:21". Krieghoff says their 470 is 1:18.9". The difference is not important and many manufacturers do not follow CIP twist specs exactly. The GSC position is that FN solids need a minimum stability factor of 2 to perform well terminally and that faster calibers need more. Here are the specs of the 500gr .470 FN from GSC. Note that a twist rate of 1:21" gives a stability factor of 2.3 which is quite sufficient for linear penetration, given the probable impact speed. It does not. If such info is on the site somewhere it is in error. Please point it out to me so that I may correct it. An ogived bullet requires a significantly higher stability factor than an FN to approach the linear performance of an FN. A shorter lead cored solid approaches this. It still does not address the probability of a jacket detaching from a core or the lack of dart and shoulder stabilisation. Goodness, do I have to repeat this incessantly and spell it out numerous times to get the meaning across? FN bullets veer or tumble when they are too long for a given twist rate. That is why GSC recommends a stability factor higher than 2 for GSC FN bullets. This is simple: Use a GSC FN that is the right length to give a stability factor better than 2. As speed (and probable impact speed) increases, the stability factor should also be increased. Faster cartridges tend to do better with higher stability factors. Will, Back up the talk with some examples. Give a link or quote where I have shouted down the competition. I sincerely hope that your book does not contain as many inaccuracies and the type of crassness that your posts do. Ignoranus, Coming from The Incoherent One the statement is meaningless, of course. | |||
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Gerard So what you are saying is, stick within the parameters we suggest - parameters which other bullet makers put on their bullets, be it recommended impact velcocities or whatever - and your bullets are fine. Stray outside these, and the bullets do as you say. That's fair as all other bullet companies put conditions on products. | |||
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From what I've seen, they still work along the border, but the whole point of this thread is about the lesser chances we have to take. In that light, yes, stick within the SF of 2 min. and you will be fine. I linked that info for JPK before, and I thought it was clear, but somehow I failed in communicating. That seems to happen. What kills me here is that every time you try and HELP someone, simply by making a suggestion, you get stomped on by those that are stuck with what they are using. So then don't listen to any of us and just keep on doing what you are doing, but don't follow up our suggestions with insults, slander and attacks to bullet design or manufacturer. To see what Will and Warrior write just burns me up because they have no reason to say it. Gerard and GSC has not attacked any company, put down any other bullets or claimed any other product is useless, he simply responds to the slander and assult from others such as Warrior and Will. Why does any company have to defend itself this much? The stuff that flies from Warrior's mouth is beyond comprehention, and I have yet to figure out why. Will jumps in and says not to trust GSC, for what? Because they respond to your degrating comments and prove points unfounded? If someone attacks you, do you not have the right to defend yourself and the company you have sacrificed and worked so hard for? If you do not believe in self defence, then you do not belong on this forum, or with any firearm either. If a bull Ele charges should you just sit there and take it? Do what you must, but do not slander. If you seek only personal gain, then slander away; I'm sure you will gain both favor and respect here for it. -Extremist "Pain is weakness leaving the body" -Instructor Victory in life is dying for what you were born to do. "I hope you live forever" -300 "Never judge an enemy by his words, he might turn out to be a better shot then a writer" http://www.gscustomusa.com | |||
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Please elaborate ... | |||
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Gerard, First, I agree with you regarding "The Incoherent One." I understand the twist issue, however, I understood you to recomend SF = 3 as a minimum. JPK Free 500grains | |||
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