Len, My guess on the vertical caused by a headwind or tailwind is absolutely negligable. My Sierra program says that a 50mph tail/head wind will cause a total of 11" of change at 1000 yards. It won't do over 50mph. That is to say that IF you have a grand total change of 50mph from bench to target, CHANGE that is, you get 11" of vertical. We have guys at williamsport who shoot in a 5mph wind and when a shot goes high , "it must have been a tailwind". Yea, right.
Vertical component of wind drift
- Thread starter Len Backus
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Brent,
I sized on a taper with the collet die in an attempt to eliminate the donut that was grabbing my bullet. As you see, the original case has a 40 degree shoulder. I did that before I found out what a pain in the ___ a 40 degree shoulder is. Never again. Reamers make a mess out of the inside of the neck, so I won't go in with one of them. That was another one of my crazy attempts to fix a problem that should never existed.
I sized on a taper with the collet die in an attempt to eliminate the donut that was grabbing my bullet. As you see, the original case has a 40 degree shoulder. I did that before I found out what a pain in the ___ a 40 degree shoulder is. Never again. Reamers make a mess out of the inside of the neck, so I won't go in with one of them. That was another one of my crazy attempts to fix a problem that should never existed.
Well S1,
I have just read Vaughn's pp 182-190 on GS. Just for the record, I did a very elementary test years ago with my swift, out to 400 yards with targets set up at various ranges with hollow target frames so the bullets passed through the paper and continued to the next target. It was a bear to set up. I found that it was mathematically possoble for my swift, a rem 700 VS-SFP to shoot better at 400 yards than it does at 100. (Not quite 4 times as big at 4 times the range). After discussing it with a reputable shooter, He told me that the "going to sleep" effect of a bullet was vaguely discussed and documented. I took from it what I could and never really tried to find more because it took an entire day to set up the targets and by some act of God, I actually had perfect conditions to test in. I figured, I'd better not ask for that again, I allready owed someone something. Now, at this time, I set my gun on a very solid bench aimed at the farthest target to be slightly right of center. The target was an 8-1/2x11 sheet of paper with 2 crosshairs on it. Why 2 I don't know because I only need one to set up. Then, I took the next target and set it up on a tripod so it was also infront of the crosshairs, and it had another mark on it for the drop compensation at it's range. These were extra sheets taped on the top of the target because of the ~20" of drop at 400 yards. And so on until I had a target at 100 yards with little crosshairs on it for an aiming spot that "should" put holes in all the targets in between. I shot that test in possibly the calmest conditions I have ever seen, save but for in a fog. All the targets are centered perfectly, (hanging on my reloading room wall). The moral of the story is, they didn't move right, left, anywhere but where my very uneducated guess would have put them.
I liken this to back when we were kids playing wiffleball. (or even adults playing with golf wiffleballs). These particular projectiles while spinning, will have all sorts of cause and effect. A golf ball may leave the club and actually CLIMB because of the spin on it. I have done it with the real thing, and wiffleballs. Now, this projectile presents the same profile to the air at any point in it's flight path. How is it then that I never see the corkscrew effect that I should be looking for and why do they not have the same gyroscopic properties that a bullet exibits. Granted, the axis of rotation is perpendicular at least at some time, but, if vaughns theory is correct, the nice round wiffleball should at some point in its travels, change axis. Basically, he is saying that the bullet WANTS to yaw. Why does it stop!
Having played with gyroscopes as a kid (had some real nice ones too!) I cannot see where the bullet in question could exhibit the behaviour you both describe. In my experience, the more you spun a gyroscope, the more stable it became. Well, we're talking about, some new kinda rpm's here. I certainly don't profess to know all the physics goin on here, but, having watched a few baseball games in my time, where they throw round balls, I'd say that air has a lot more to do with this than meets the eye. I will not way that your conclusion is wrong, just that there is a better chance that both conditions/results exist.
Just for the record, I like my theory better
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I have just read Vaughn's pp 182-190 on GS. Just for the record, I did a very elementary test years ago with my swift, out to 400 yards with targets set up at various ranges with hollow target frames so the bullets passed through the paper and continued to the next target. It was a bear to set up. I found that it was mathematically possoble for my swift, a rem 700 VS-SFP to shoot better at 400 yards than it does at 100. (Not quite 4 times as big at 4 times the range). After discussing it with a reputable shooter, He told me that the "going to sleep" effect of a bullet was vaguely discussed and documented. I took from it what I could and never really tried to find more because it took an entire day to set up the targets and by some act of God, I actually had perfect conditions to test in. I figured, I'd better not ask for that again, I allready owed someone something. Now, at this time, I set my gun on a very solid bench aimed at the farthest target to be slightly right of center. The target was an 8-1/2x11 sheet of paper with 2 crosshairs on it. Why 2 I don't know because I only need one to set up. Then, I took the next target and set it up on a tripod so it was also infront of the crosshairs, and it had another mark on it for the drop compensation at it's range. These were extra sheets taped on the top of the target because of the ~20" of drop at 400 yards. And so on until I had a target at 100 yards with little crosshairs on it for an aiming spot that "should" put holes in all the targets in between. I shot that test in possibly the calmest conditions I have ever seen, save but for in a fog. All the targets are centered perfectly, (hanging on my reloading room wall). The moral of the story is, they didn't move right, left, anywhere but where my very uneducated guess would have put them.
I liken this to back when we were kids playing wiffleball. (or even adults playing with golf wiffleballs). These particular projectiles while spinning, will have all sorts of cause and effect. A golf ball may leave the club and actually CLIMB because of the spin on it. I have done it with the real thing, and wiffleballs. Now, this projectile presents the same profile to the air at any point in it's flight path. How is it then that I never see the corkscrew effect that I should be looking for and why do they not have the same gyroscopic properties that a bullet exibits. Granted, the axis of rotation is perpendicular at least at some time, but, if vaughns theory is correct, the nice round wiffleball should at some point in its travels, change axis. Basically, he is saying that the bullet WANTS to yaw. Why does it stop!
Having played with gyroscopes as a kid (had some real nice ones too!) I cannot see where the bullet in question could exhibit the behaviour you both describe. In my experience, the more you spun a gyroscope, the more stable it became. Well, we're talking about, some new kinda rpm's here. I certainly don't profess to know all the physics goin on here, but, having watched a few baseball games in my time, where they throw round balls, I'd say that air has a lot more to do with this than meets the eye. I will not way that your conclusion is wrong, just that there is a better chance that both conditions/results exist.
Just for the record, I like my theory better
Hey S1,
Are you saying that you buy his computer model stuff? You Just differ on the extrapolation past 200 yards?
I just read real quick last night and that's not good on something he's carrying so deep. It just seemed like, the more I read, the more I felt that subjectivity from tunnel-vision was setting in for him. He basically ignores the air effect entirely after the bullet gets yawed. See what I mean. I'll reread it tonight and be objective again.
Keep in mind, I'm laughin too! We really have too much time on our hands to even argue BS like this. When we all get done, I'm gonna aim 4" high and 12" left for a left to right wind!
For me at my stage, this is a "1% problem" and I have some "20% issues" to deal with. I just wasted a lot of time on an annealer that's gonna fix a .001% problem.
Talk to ya later. I also have to get a flash hole reamer from ya some time soon. I'll go back and look up your address for the check. Let me know if you don't have any or if it's gonna be a while.
Are you saying that you buy his computer model stuff? You Just differ on the extrapolation past 200 yards?
I just read real quick last night and that's not good on something he's carrying so deep. It just seemed like, the more I read, the more I felt that subjectivity from tunnel-vision was setting in for him. He basically ignores the air effect entirely after the bullet gets yawed. See what I mean. I'll reread it tonight and be objective again.
Keep in mind, I'm laughin too! We really have too much time on our hands to even argue BS like this. When we all get done, I'm gonna aim 4" high and 12" left for a left to right wind!
For me at my stage, this is a "1% problem" and I have some "20% issues" to deal with. I just wasted a lot of time on an annealer that's gonna fix a .001% problem.
Talk to ya later. I also have to get a flash hole reamer from ya some time soon. I'll go back and look up your address for the check. Let me know if you don't have any or if it's gonna be a while.
G
Guest
Guest
4MESH, spend some time studying the laws of gyrscopic precession before picking a theory.
G
Guest
Guest
4Mesh,
I think that his actual tests were done at short distance with few data points. This led him to believe that it is linear. I do not believe it is linear, in fact I would bet a lot of money the vertical component is not linear. No matter how you slice it mathmatically, actual testing and observation show me that it is not linear.
Len,
I have observed the largest vertical component shifts when shooting at 1,000 yards when the wind is blowing from 10:30 to 4:30, and have observed 3/4 MOA vertical on many occasions. A shift of 1/2 MOA is common.
I think that his actual tests were done at short distance with few data points. This led him to believe that it is linear. I do not believe it is linear, in fact I would bet a lot of money the vertical component is not linear. No matter how you slice it mathmatically, actual testing and observation show me that it is not linear.
Len,
I have observed the largest vertical component shifts when shooting at 1,000 yards when the wind is blowing from 10:30 to 4:30, and have observed 3/4 MOA vertical on many occasions. A shift of 1/2 MOA is common.
S1,
OK. I see what you mean. I place myself in a category somewhat like yourself on this where I think that from observation alone, some holes are shot in the idea. I've now had 2 days of discussion about this subject and read the entire section and related sections again, this time with more reading comprehension applied. I still disagree with this in part, if not in majority.
I was up till 2am going over the theory and calculations last night and the A #1 thing that I see that blows a hole in this is the fact that if you shoot hardened ball bearings out of a smooth bore gun, wind will not affect them according to harold. Bzzzz. No way. The way I see it, the bullet should attempt to drive INTO the wind if what he is saying is correct. He shows a picture of a bullet with a drag line and reverses the effect that I feel would exist, if one does. My experience with gyroscopes, probably like yours, is limited to the toys I had as a kid, and the one in my new binoculars that does not count. A gyroscope, will move freely in space anywhere perpendicular to it's axis of rotation. But, it won't move (or tries not to) move axialy against the rotational axis. What he contends is that the bullet is happy to pitch or yaw in that direction but will not blow in the direction that it should be happy to move. I'm just not sold on the idea, it is interesting, and I 100% agree that it is NOT a straight line progression. I would agree if one of you said that it was a straight line acceleration. This is plausable.
Another thing that shoots this in the foot is that in his section on muzzle blast, which is also referenced from Ch 6, he places a screen with a bunch of wickers on it to shoot through and examine muzzle blast. Now, he placed the screens at 18' from the muzzle. He contends there that the bullet has only just left the effect of the supersonic muzzle cloud at the time it passes the screen, but in the Gyro/Prec section and modeling, he shows a fast and slow precession out to 200 yards. There he says that the bullet has already aligned itself to the drag line by the end of the first fast precession. BS. It's still sitting in a supersonic cloud. I count on one example, the best one as he says, 11 slow precessions at 200yards, and in that first slow, 11 fast precessions. He says that by the end of the first fast precession, the bullet has already chosen its attitude aligned to the drag vector. Now, discluding deceleration due to flight time, that means that the bullet in the first 19.83 inches, has allready determined it's final home. In a perfect world and with dead constant wind from bench to target, as the model suggests. I've never heard such a crock of @#$@# in my life. I do not doubt that there could be some substantiated facts in this section, but, I will not buy this even a little bit. I AM going to test this with a 100mph wind for myself and determine if there is even a chance that there is truth here, and I will check it this weekend. I'll let you know how it turns out.
This is fun, ya know. I just wish it was simpler so I could move on!
OK. I see what you mean. I place myself in a category somewhat like yourself on this where I think that from observation alone, some holes are shot in the idea. I've now had 2 days of discussion about this subject and read the entire section and related sections again, this time with more reading comprehension applied. I still disagree with this in part, if not in majority.
I was up till 2am going over the theory and calculations last night and the A #1 thing that I see that blows a hole in this is the fact that if you shoot hardened ball bearings out of a smooth bore gun, wind will not affect them according to harold. Bzzzz. No way. The way I see it, the bullet should attempt to drive INTO the wind if what he is saying is correct. He shows a picture of a bullet with a drag line and reverses the effect that I feel would exist, if one does. My experience with gyroscopes, probably like yours, is limited to the toys I had as a kid, and the one in my new binoculars that does not count. A gyroscope, will move freely in space anywhere perpendicular to it's axis of rotation. But, it won't move (or tries not to) move axialy against the rotational axis. What he contends is that the bullet is happy to pitch or yaw in that direction but will not blow in the direction that it should be happy to move. I'm just not sold on the idea, it is interesting, and I 100% agree that it is NOT a straight line progression. I would agree if one of you said that it was a straight line acceleration. This is plausable.
Another thing that shoots this in the foot is that in his section on muzzle blast, which is also referenced from Ch 6, he places a screen with a bunch of wickers on it to shoot through and examine muzzle blast. Now, he placed the screens at 18' from the muzzle. He contends there that the bullet has only just left the effect of the supersonic muzzle cloud at the time it passes the screen, but in the Gyro/Prec section and modeling, he shows a fast and slow precession out to 200 yards. There he says that the bullet has already aligned itself to the drag line by the end of the first fast precession. BS. It's still sitting in a supersonic cloud. I count on one example, the best one as he says, 11 slow precessions at 200yards, and in that first slow, 11 fast precessions. He says that by the end of the first fast precession, the bullet has already chosen its attitude aligned to the drag vector. Now, discluding deceleration due to flight time, that means that the bullet in the first 19.83 inches, has allready determined it's final home. In a perfect world and with dead constant wind from bench to target, as the model suggests. I've never heard such a crock of @#$@# in my life. I do not doubt that there could be some substantiated facts in this section, but, I will not buy this even a little bit. I AM going to test this with a 100mph wind for myself and determine if there is even a chance that there is truth here, and I will check it this weekend. I'll let you know how it turns out.
This is fun, ya know. I just wish it was simpler so I could move on!
My nonexpert understanding of Robert McCoy's dissertation on the subject: For the .30 Ball at 2800 fps--.5"/10 mph rangewind at 600 yards. A minor concern I'd think.
I may not understand what he meant but my understanding is that he attributes vertical effect of crosswind to projectile jump, which I think is a result of gyroscopic precession as S1 said. I've had my head in the Rinker/Vaugh/McCoy trough for the last couple of months and I'll propably be catatonic and drooling anytime now.
And all I wanted when I showed up here was to learn about long range shooting.
Does anybody know how data is deduced or reduced from spark shadowgraph photos? I see no reference points.
I may not understand what he meant but my understanding is that he attributes vertical effect of crosswind to projectile jump, which I think is a result of gyroscopic precession as S1 said. I've had my head in the Rinker/Vaugh/McCoy trough for the last couple of months and I'll propably be catatonic and drooling anytime now.
Does anybody know how data is deduced or reduced from spark shadowgraph photos? I see no reference points.
Vertical movement due to effects of head or tail wind(rangewind). .5" for that package at 600 yds. per 10 mph of wind. I understand only that he attributes vertical movement due to crosswind to projectile jump---I think. His stuff is a bit deep, my mind a bit slow.
4mesh,
I finally had the time to read this thoroughly...not sure I understand everything you're saying. Your wiffle ball analogy is not relevant to this issue. Round ball aerodynamics have different rules at different velocities and with different diameters. It has a lot to do with Reynolds Numbers. As I understand it, the large magnus effect that causes baseballs to curve disappears for the most part at firearm velocities, as an example. I do not fully understand all(maybe most) of the science of external ballistics but I do know this: Vaughn pretty much knows his stuff. If you want to cross reference his "facts" try "Modern Exterior Ballistics" by Robert McCoy. Another fellow that knows his stuff. Oh by the way, get a scientific calculator if you want to follow the bouncing ball. It is "advanced", the $90 +/- pricetag a bargain. Luck to you.
I finally had the time to read this thoroughly...not sure I understand everything you're saying. Your wiffle ball analogy is not relevant to this issue. Round ball aerodynamics have different rules at different velocities and with different diameters. It has a lot to do with Reynolds Numbers. As I understand it, the large magnus effect that causes baseballs to curve disappears for the most part at firearm velocities, as an example. I do not fully understand all(maybe most) of the science of external ballistics but I do know this: Vaughn pretty much knows his stuff. If you want to cross reference his "facts" try "Modern Exterior Ballistics" by Robert McCoy. Another fellow that knows his stuff. Oh by the way, get a scientific calculator if you want to follow the bouncing ball. It is "advanced", the $90 +/- pricetag a bargain. Luck to you.
CatShooter
Well-Known Member
Brent...
The problem with that (top) picture is...
... in reality, the center of gravity in a match bullet is towards the rear of the bullet, and the center of aerodynimic drag (center of pressure) is in FRONT of the center of gravity... so if side air pressure were to be responsible for turning (it isn't), the bullet would turn left, instead of right (as shown in the drawing).
CatShooter.
[ 04-13-2003: Message edited by: CatShooter ]
The problem with that (top) picture is...
... in reality, the center of gravity in a match bullet is towards the rear of the bullet, and the center of aerodynimic drag (center of pressure) is in FRONT of the center of gravity... so if side air pressure were to be responsible for turning (it isn't), the bullet would turn left, instead of right (as shown in the drawing).
CatShooter.
[ 04-13-2003: Message edited by: CatShooter ]
Cat,
I think you will find that the longitudinal balance point has little to do with the eventual line of drag as we are thinking of the air creating the drag and really it is the bullet that makes it's own. This is a crazy deal.
Max and S1.
OK. I said that I WOULD test this and attempt to rethink the idea if I could "See" something that would make me beleive I should entertain any other possibilities. Well, I have seen results that incline me to say that you and your cohorts are absolutely correct on the bullet flying to it's destination instead of being sent there.
I stand corrected.
Since the onset of this thread I have known that there is a tremendous difference between airodynamics and hydrodynamics, Air, Liquid and Solid physics. I simply could not see with my limited education on the subjects how the common sense physics do not apply. I tried to see it, but, till I got hit with it, it was foggy. Well, the main thing that Vaughn never points out that I did know ahead of time was that a wiffle ball travels through air and a bullet does not. Air, above the speed of sound is a solid. Or, at least it's dynamics for flight are treated as such. I think that Vaughn's statement of how fast the bullet turns into the wind is incorrect but that He most likely never expected anyone to care enough to actually test the theory while the bullet is still in the supersonic muzzle blast. You can affect the hell out of it shortly therafter.
Now, this afternoon I had the opportunity to test this at 1024 Yards, twice, and video'ed the effects. (actually the cause).
It's a most interesting discovery.
The most disheartening part of all this is that after all this ****ing around, I still aimed 36" left and 10" high in order to center and was DEAD down the middle of the target. Now, If I could just fix my 20% issues, My infinite knoledge of this 1% issue might help me to win but I have many other problems to solve first and they cause me a lot bigger problem at this point.
No doubt, at some point very near in the future, my newfound understanding of this may come in handy. For now, wind blows my group all over hell and my gun problems compound this to where it's overwhelming. I cannot beleive that I have a gun that shoots as good as mine does, and have a gun that shoots as bad as it does.
I hope someone else gets something out of all this cause I have finger fatigue.
I think you will find that the longitudinal balance point has little to do with the eventual line of drag as we are thinking of the air creating the drag and really it is the bullet that makes it's own. This is a crazy deal.
Max and S1.
OK. I said that I WOULD test this and attempt to rethink the idea if I could "See" something that would make me beleive I should entertain any other possibilities. Well, I have seen results that incline me to say that you and your cohorts are absolutely correct on the bullet flying to it's destination instead of being sent there.
I stand corrected.
Since the onset of this thread I have known that there is a tremendous difference between airodynamics and hydrodynamics, Air, Liquid and Solid physics. I simply could not see with my limited education on the subjects how the common sense physics do not apply. I tried to see it, but, till I got hit with it, it was foggy. Well, the main thing that Vaughn never points out that I did know ahead of time was that a wiffle ball travels through air and a bullet does not. Air, above the speed of sound is a solid. Or, at least it's dynamics for flight are treated as such. I think that Vaughn's statement of how fast the bullet turns into the wind is incorrect but that He most likely never expected anyone to care enough to actually test the theory while the bullet is still in the supersonic muzzle blast. You can affect the hell out of it shortly therafter.
Now, this afternoon I had the opportunity to test this at 1024 Yards, twice, and video'ed the effects. (actually the cause).
It's a most interesting discovery.
The most disheartening part of all this is that after all this ****ing around, I still aimed 36" left and 10" high in order to center and was DEAD down the middle of the target. Now, If I could just fix my 20% issues, My infinite knoledge of this 1% issue might help me to win but I have many other problems to solve first and they cause me a lot bigger problem at this point.
No doubt, at some point very near in the future, my newfound understanding of this may come in handy. For now, wind blows my group all over hell and my gun problems compound this to where it's overwhelming. I cannot beleive that I have a gun that shoots as good as mine does, and have a gun that shoots as bad as it does.
I hope someone else gets something out of all this cause I have finger fatigue.
