Next-- wind/bullet movement question, where does the wind effect the bullet the most?

JerrySharrett

JerrySharrett

Senile Member
The situation-we have wind flags set up at 25, 50, and 75 yards for a target that is at 100 yards.

To start, the average benchrest bullet is spinning about 185,000 rpm. Do you believe the theory that the wind actually re-aims the axis of rotation of the bullet and thus the wind closest to the bench has more effect on where the bullet impacts? Realizing the wind to re-aim the bullet must push on the side of the bullet. Since the bullet has a larger "footprint" at the back than it does on its point, how does the wind push the bullet nose around?? Why would the wind not push the base more than the point, thus re-aiming the bullet into the wind?

Or, is a bullet like an airplane traveling along that same flight path, in the same air mass, meaning the distance from the last flag to the target has more effect since the bullet is in the segment for a longer period of time since it has slowed down?


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Jerry,
This subject has been discussed and disagreed about with lots of citations of various references, and the last time, after everyone had spent their energy on explanations about the mechanism of wind drift that were based on spitzer shaped bullets, and chastising anyone who even slightly mentioned anything close to wind pushing on sides of bullets, I was the rude fellow that pointed out that round balls are the worst for wind drift, and that they have no point. Now I am going to pop some corn and watch.
Boyd
 
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In your example for three equally spaced segments on an open range without terrestrial influences, the ratio of 3x, 2x, & 1x is pretty close. In other words is you had a total push of .6 at the target with an identical wind all the way to the target, the first is .3, the second is .2 and the last is .1.
 
If you are going to design and use electronic wind flags, distilling all of their inputs into a single plus or minus number requires placing accurate values on the relative effect of wind at the various distances that the flags are posted. I believe that Jerry has done more work on electronic wind flags than anyone on the planet, and he has done a lot of testing to come up with the values that he has just given us close approximations of for free.
 
All ranges aren't the same, I can say I've shot on some ranges and it didn't seem to matter what the far flag was doing as long as the second and third flag were showing what I was watching for the bullet went in the same hole and all the front flag had to show was the same general direction as the 2nd and 3rd flag.

I think it's range and condition dependant how and where that condition affects the bullet.
 
I think we are going to need quantum mechanics to figure this out, any physicists on line?
Bill
 
Harold Vaughn's Accuracy Facts book has quite bit regarding the science explaining wind drift. Complex reading if you can digest it. Most will just believe what they believe based on sporadic empirical data they have observed rather than any sort of testable (time consuming and expensive) data collection.
 
geo.ulrich said:
The bullet that STABILIZES quickest will be the least affected by wind.
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George Walt Berger has made that argument to me many times. He insists we we're shooting too fast and that a slower velocity, say around 3100-3135, the bullet will go to sleep much sooner.


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In the past, when working up with an unfamiliar powder (in a 6PPC) the size of the bullet holes was smaller with lower charges, then as the loads warmed up, they changed noticeably. It is an easy experiment to do.
 
The tip of the iceberg

Jerry H said:
Harold Vaughn's Accuracy Facts book has quite bit regarding the science explaining wind drift. Complex reading if you can digest it. Most will just believe what they believe based on sporadic empirical data they have observed rather than any sort of testable (time consuming and expensive) data collection.
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Yep read Harold's book a number of times. Much of the data I agreed with some not. But on the subject of how a bullet will behave in a given set of conditions is way too complex to try and cover on a forum. Suffice to say I think I have a solution. Take sighter shots and hope the conditions that produce that result continue until the record round is fired.
Andy.
 
Boyd Allen said:
In the past, when working up with an unfamiliar powder (in a 6PPC) the size of the bullet holes was smaller with lower charges, then as the loads warmed up, they changed noticeably. It is an easy experiment to do.
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Many, most??, top shooters look at the hole size in determining the quality of the tune. i.e Is the load at the very peak of tune?


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JerrySharrett said:
Many, most??, top shooters look at the hole size in determining the quality of the tune. i.e Is the load at the very peak of tune?


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I don't understand this. I hear this often, and people seem to be able to glean useful information from reading the holes in the paper. But how many revolutions does the bullet make as it passes through the paper? What actually influences the size of the hole in the paper?
 
The smaller the hole, the less the wobble of the bullet as it passes through the paper. As George alluded to earlier, the bullet is asleep or well stabilized. Also, brand new backing material will make smaller holes as well.
 
James Lederer said:
I don't understand this. I hear this often, and people seem to be able to glean useful information from reading the holes in the paper. But how many revolutions does the bullet make as it passes through the paper? What actually influences the size of the hole in the paper?
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here is a closeup of some shots at 200 yards with one of my barrels. as you an see, the bullet is still wobbling as it passes thru the paper. and, yes, this barrel was extremely wind sensitive.

 
Newton figured this out

Newton's First Law of Motion states that a body at rest will remain at rest unless an outside force acts on it, and a body in motion at a constant velocity will remain in motion in a straight line unless acted upon by an outside force.

The bullet will stay in motion longer if the wind is close to the muzzle of the rifle. If the wind is blowing consistently from muzzle to target the wind at the muzzle has proportionately greater affect than the wind a few feet from the target. Velocity, spin, etc...has some effect but I have to keep it simple for me!

Earlier, I had it in my mind that a bullet would quit moving when it passed out of the wind that pushed it. It can't until something stops it from moving!

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AND...Came back to say this...A hummer barrel seems to go against anything Newton wrote or said or otherwise. Perhaps I'm looking at it the wrong way.....

What George said...but don't know why!
 
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Interior Ballistics v Exterior Ballistics

Wilbur said:
Newton's First Law of Motion states that a body at rest will remain at rest unless an outside force acts on it, and a body in motion at a constant velocity will remain in motion in a straight line unless acted upon by an outside force.

The bullet will stay in motion longer if the wind is close to the muzzle of the rifle. If the wind is blowing consistently from muzzle to target the wind at the muzzle has proportionately greater affect than the wind a few feet from the target. Velocity, spin, etc...has some effect but I have to keep it simple for me!

Earlier, I had it in my mind that a bullet would quit moving when it passed out of the wind that pushed it. It can't until something stops it from moving!

____________________________________

AND...Came back to say this...A hummer barrel seems to go against anything Newton wrote or said or otherwise. Perhaps I'm looking at it the wrong way.....

What George said...but don't know why!
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Barrels only affect bullets whilst their in the barrel. Interior ballistics. Once they leave the muzzle it's all exterior ballistics. Lets not confuse the two.
Andy
 
Everyone here would be well served to read AND understand Robert McCoys Modern exterior ballistics I know some that have but I am quite sure in discussions I have had or read most have not. Google and Amazon should lite up now.......:D
 
Andy Cross said:
Barrels only affect bullets whilst their in the barrel. Interior ballistics. Once they leave the muzzle it's all exterior ballistics. Lets not confuse the two.
Andy
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The main difference is the effect of what it does with a bullet, in barrel bullet rotates on its center axis. When it leaves barrel it rotates around its center of gravity.....
 
Bottom line is how the rifle shoots overall...which is predicated mostly by what happens within the rifle...all else being equal.
 
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