The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores Do bullets yaw?Go | New | Find | Notify | Tools | Reply | |
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This was posted on anther forum and no one there will or can answer the question. Do bullets yaw for the first 25 yards? | ||
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All bullets yaw (tip) to some extent. As velocity increases and as bullet length increases, yaw also increase. So a 460 wby shooting a 400 grain FN bullet at 3000 fps will tend to cause more bullet yaw than a 45-70 shooting the bullet at 1800 fps, if the same twist is used. If the twist rate used is fast enough, yaw is rather minimal, even close to the muzzle. If the twist rate is a bit slow and velocities are high, it can take 25 yards or even 75 yards (.223 with 1:14 twist shooting 62 gr bullets) for the yaw to quiet down. Art Alphin realized this problem and went with quick twist rates in the A-Square cartridges because dangerous game is sometimes shot up close. However, with a normal twist rate and a standard weight lead core bullet in one of the nitro express cartridges, you do not need to stand off 25 yards to take a shot due to bullet yaw. Just get as close as you want. With a 1:16" 460 Wby using 500 grain monolithics at 2700 fps, it may be a good idea to stand back 25 yards or more due to bullet yaw. | |||
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yes and its contageous... 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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i think it was a yes or no answer but i think i just got a doctorate reading that post...good one alf  | |||
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if i read his post correctly the question is does the bullet "true" itself in the beginning of its flight. | |||
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as above, I believe there is a difference between yawing and a projectile stabilizing. boattails need a hundred yards or so to settle down if my memory serves. is a bullet yawing when it keyholes, and why does it?
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first, define "Yaw" we can NOT use the concept of "deviation from course" as that would entail the rifle shooting several to many times MOA.. patterning rather than grouping. that is, unless, of course, one defines the above as normal. the description that defines can't be considered ONLY "an angle, to the right or left, determined by the direction of motion of an aircraft or spacecraft and its vertical and longitudinal plane of symmetry." Nor only the same changed to define UP/DOWN. In fact, we are actually talking about HELIXING (yaw is an aviation term)
Where, if one accepts the concept, we would use "Cone" as that points to being MOA "down range" Is it signifigant at big bore velocities? not if the barrel has enough twist to stablize the bullet, period  nope http://470mbogo.com/BigBores/BigBores11.html Does bullet concentricy and angle of attack have far more to do with it? Of course but, some people will argue for weeks about it. opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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When Alf answers I know longer understand the question.  _________________________________ AR, where the hopeless, hysterical hypochondriacs of history become the nattering nabobs of negativisim. | |||
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Alf, I'm just being my normal flippant self. Most people wouldn't take the time and trouble you do to lay it all out. _________________________________ AR, where the hopeless, hysterical hypochondriacs of history become the nattering nabobs of negativisim. | |||
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All I want to know is, do they kill Buffalo from muzzle to 50 yds when I shoot them?   ....Mac >>>===(x)===> MacD37, ...and DUGABOY1 DRSS Charter member "If I die today, I've had a life well spent, for I've been to see the Elephant, and smelled the smoke of Africa!"~ME 1982 Hands of Old Elmer Keith  | |||
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500 Grains, What would the position be when the twist is slow and the velocity is also slow, like in a 9,3x62 mm. Twist is 1-in-14" and the velocity is around 2,250 to 2,300 fps. a) Would you say it is fine to use a .366/286-gr Solid bullet on DG under 25 yards based on the above parameters? [Bullets such as A-Square & Barnes] b) Then, secondly would it do much worse with the longer 320-gr Woodleigh Steel FMJ bullet? I am trying to understand the principle that you are laying down or that you have observed. Thanks Warrior | |||
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I have been told by some of the old elephant hunters that the bullet "yaws" and does not come out in a true flat spin for 5 to 10 yards, and when this happens the bullets may not travel in a straight line, or fail to penetrate, thus wounding. I pretty much accepted that as fact based on the therory that they might know what they are talking about due to their extensive experience and if they were wrong, no harm would come from it. Also I have read this in several articles as I am sure some of you have. Probably of more concern is that if something goes wrong then one has time to correct the situation at 25 yards and might not at point blank. The main thing I am saying is the option of range is the shooters and not to be dictated by others. I realize that in many cases one must be prepared to shoot at 10 yards or even point blank due to the thick bush where elephant are concerned and also in the high grass with buffalo. Anyone who has hunted buffalo to any extent knows that you get shots from 10 to 200 plus yards, your option is to walk away in either case or take the shot. I would not let a 45 to 50 inch buff walk off at either range and I don't know anyone that would, except those that claim to on forums. Ray Atkinson Atkinson Hunting Adventures 10 Ward Lane, Filer, Idaho, 83328 208-731-4120 rayatkinsonhunting@gmail.com | |||
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Next I am on a cap buff hunt I will tape the yaw chart to my rifle stock and make sure to back up to that minimum distance before shooting. Mike Legistine actu quod scripsi? Never under estimate the internet community's ability to reply to your post with their personal rant about their tangentially related, single occurrence issue.  What I have learned on AR, since 2001: 1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken. 2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps. 3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges. 4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down. 5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine. 6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle. 7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions. 8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA. 9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not. 10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact. 11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores. 12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence. 13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances. | |||
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guys, have figured it out...  The repose angle of yaw (or yaw of repose, also called equilibrium yaw) is the angle, by which the momentary axis of precession deviates from the direction of flight (see figure ). As soon as the transient yaw induced at the muzzle has been damped out for a stable bullet, the yaw angle d equals the yaw of repose. The magnitude of the yaw of repose angle is typically only fractions of a degree close to the muzzle, but may take considerable values close to the summit especially for high-elevation angles. The occurrence of the yaw of repose is responsible for the side drift of spin-stabilized projectiles even in the absence of wind. The spin-dependent side drift is also called derivation. It can be shown that for right-hand twist, the yaw of repose lies to the right of the trajectory. Thus the bullet nose rosettes with an average off-set to the right, leading to a side drift to the right. The above formula for the yaw of repose vector is an approximation for stable bullet flight. sorry, just wanted to look like i am as smart as alf  i am a cut and paste genious  577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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Along with "yaw" charts we need the "pitch" and "roll" charts taped to the other side of the stock butt as well. And, we certainley need the "translational velocity", "rotational velocity", and "precessional velocity" charts taped to the forend of the rifle. Rifling twist ratio is key driver not projectile length. Impact velocity is key driver for selecting bullet construction. Ignorance is bliss. Posters that can't size a case without getting it stuck in the sizing die need not worry themselves about thse trivial matters that took about 800 years for science to figure out. One less thing.... | |||
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ALF Salutations! Is there a calculation of Mutation in Nutation Duration regarding rotation gyration to get nutation emancipation and is there a rationalization for notation proration leading to nutation termination? Can that help as a lesson in regard to regression in precession during a range session? Please bear in mind that most of us never got past all that angle of dangle stuff in physics class... SCI Life Member DSC Life Member | |||
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jim, you speak "jesse jackson" quite well... 577 BME 3"500 KILL ALL 358 GREMLIN 404-375 *we band of 45-70ers* (Founder) Single Shot Shooters Society S.S.S.S. (Founder) | |||
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With a mono bullet, I would be inclined to either go about 10% lighter with a standard twist, or go to a faster twist (if building a custom gun). I have not tested the 320 gr Woodleigh solid compared to the 286 grain solid, but a friend of mine has and found that the 286 grain out-penetrates the 320 grain. Perhaps this is due to excessive yaw and early tipping by the 320 grain. As you know, the Barnes X .416 400 grain and .458 500 grain are known to tumble on impact some of the time. These are very long bullets, which seem not to stabilize in a standard twist barrel (i.e., excessive yaw). For a more erudite response, I will have to refer you to Gerard at www.gscustom.co.za as he is an expert in this area. | |||
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500 Grains, Thanks for your response. It is certainly an interesting observation, since the momentum value of the much heavier bullet will by far outstrip the momentum of the lighter bullet. That is significant enough then to question the desirability or wisdom of choosing the 320-gr Wdl FMJ for dangerous game work. It surely intrigues me then, why Ganyana has been using this bullet up to now and not the lighter 286 grain version. Just some bullet length figures: 250 gr Barnes-X: 34.16 mm 286 gr Barnes-X: 38.1 mm 286 gr Barnes Solid: 35.05 mm 286 gr Wdl FMJ: 32.33 mm 320 gr Wdl FMJ: 35.86 mm Did your friend do a controlled test in an artificial medium or live game? Also what was the distance and the observed difference in penetration? Warrior | |||
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You can say that again.  "Science only goes so far then God takes over." | |||
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Just what is excessive yaw? Rusty We Band of Brothers! DRSS, NRA & SCI Life Member "I am rejoiced at my fate. Do not be uneasy about me, for I am with my friends." ----- David Crockett in his last letter (to his children), January 9th, 1836 "I will never forsake Texas and her cause. I am her son." ----- Jose Antonio Navarro, from Mexican Prison in 1841 "for I have sworn upon the altar of god eternal hostility against every form of tyranny over the mind of man." Thomas Jefferson Declaration of Arbroath April 6, 1320-“. . .It is not for glory, nor riches, nor honours that we are fighting, but for freedom - for that alone, which no honest man gives up but with life itself.” | |||
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JMHO, Yaw is misused here as it will not be possible with a spinning bullet. Yaw is side to side movement and bullets oscillate around the center of rotation. If a bullet started to wiggle to the side in any direction gyroscopic precession would cause it to immediately start oscillating. Frank "I don't know what there is about buffalo that frightens me so.....He looks like he hates you personally. He looks like you owe him money." - Robert Ruark, Horn of the Hunter, 1953 NRA Life, SAF Life, CRPA Life, DRSS lite | |||
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Ouch! That;s going to leave a mark! SCI Life Member DSC Life Member | |||
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Fjold, Would that have anything to do with your avatar's movement? And for us lefties, would that reverse her oscillation?  .395 Family Member DRSS, po' boy member Political correctness is nothing but liberal enforced censorship | |||
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I'm a lefty and those are already set for reverse oscillation. Frank "I don't know what there is about buffalo that frightens me so.....He looks like he hates you personally. He looks like you owe him money." - Robert Ruark, Horn of the Hunter, 1953 NRA Life, SAF Life, CRPA Life, DRSS lite | |||
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Twist rate,bullet characteristics and powder characteristics must perform in such a way that the bullet leaves the barrel like a perfectly spiralling football.I believe group size at the point of impact tells us how well everything is working.An improperly thrown football cannot all of a sudden become a perfect spiral.It is not a missile where energy is imparted to it while in flight.IMO the 25yd yaw quote does not make sense. | |||
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What was this thread about again??  "Science only goes so far then God takes over." | |||
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Again I think we are getting ahead of practacality. I've heard of bullet "yaw", and couldn't care less. My little .223 with 80gr bullets was supposed to be inaccurate until 200 yards because of "yaw." Well guess what, it gets worse as range increases, as is natural. But with DG, any slight wobble, possibly from the bullet changing from spinning in the barrel around it's roundness, to spinning in air due to its centre of gravity, would be nothing compared to its hitting an angleing surface of a skull/ hide/ leg bones etc. And who would NOT shoot a charging buff at 8 paces and closing incase the bullet "haden't gone to sleep." ??  | |||
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As stated above Art Alphin made this observation and he wrote about it in his book (Any shot you want). It is an important aspect and deserves some discussion/appreciation by us and any tests done to confirm it is obviously valuable. It is these type of subjects that make ballistics interesting. Warrior | |||
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Warrior You may want to consult some people that have actually used the 320 gr Woodleigh. It was introduced exactly for the purpose of improving on penetration over a 286 gr projectile. | |||
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Regarding "Yaw", are people here trying to say group size is going to be bigger closer to the muzzle than at say 25 metres? The only YAW I know of is an arrow takes a while to stabilize due to its very low speed, great length, and need to build up rotational speed to stabilize. I would have thought a bullet has maximum rotational speed when it leaves the barrel, after that it is slowing down? | |||
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Well said. Some guys forget 'academics' often loose touch with practicality. | |||
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NitroX, I would have thought so as well, but Dan's friend seem to have evidence to the contrary and sharing information such as this makes AR a unique place in the gun world. That's why we need to explore it further. Warrior | |||
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The ones I have are marked 360 No 2, and I thought they were designed for that cartridge. In softs, I have found that the Woodleigh 320 penetrated deeper than the Woodleigh 286. It also expanded less (lower velocity). I was going to perform an experiment on ele to see whether the 286 or 320 solid penetrated further until my friend told me he had already done it and the 286 was the clear winner. The subject was elephant. However, I did not get data from him so I have nothing to repeat here. | |||
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Thanks for Noticing, John
opinions vary band of bubbas and STC hunting Club Information on Ammoguide about the416AR, 458AR, 470AR, 500AR What is an AR round? Case Drawings 416-458-470AR and 500AR. 476AR, http://www.weaponsmith.com | |||
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Sorry I rarely read your posts so missed it. | |||
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