Wind effects on bullets by alinwa and Cheechako

Vern

Vern

Morethan1waytoskinacat
You two guys have a great subtopic started. So lets continue here.

One thing that was brought up but I seemed to be missing something on was
if a bullet drifts/is pushed 1" at 100 yards is it pushed 10" at 1000 yards?

What was the answer to that?
 
Vern said:
You two guys have a great subtopic started. So lets continue here.

One thing that was brought up but I seemed to be missing something on was
if a bullet drifts/is pushed 1" at 100 yards is it pushed 10" at 1000 yards?

What was the answer to that?
Click to expand...
I went and found the original discussion before posting here so I would understand the question. In the original scenario where there was crosswind between the bench at 100 yards and none afterwards then the bullet would most likely hit somewhere 10" from center at 1000 due to the now straightline path from 100 to 1000. Not exactly becasue the new path would be a tangent to the perviouly curved path. So long as the crosswind is constant from bench to target, the drift rate will increase. That same shot, were it measured at 50 yards would have been less than 1/2" off center.
 
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I have attached an example of a wind drift chart (mislabeled trajectory example) The 100 yard deflection is .94". 200 is 3.28. 1,000 is 149.68. This is from a program called Quick Target.
 

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As I said before, this has been discussed to death. Go back and read this old thread.

I notice that we are now using the term "drift" to describe the effect of a crosswind. I, and most ballisticians, prefer "deflection". Drift is the term normally used to describe the effect of bullet spin. No big deal, but we need to keep track of the words we use.

I'm still a believer of McDonald & Almgren explanation in the Sierra manual. Al said they have changed the text but I am going to call them just to make sure. As I recall, there is another thread on this Forum where Bryan Litz essentially agreed with the Sierra ballisticians. I haven't been able to locate it, however.

The following thread also discusses the wind deflection on a round ball, something that bothered me from the first page of this thread.

http://benchrest.com/showthread.php...ullets-amp-Balls&highlight=McDonald+++Almgren

ray
 
I called Sierra and they said that the Ballistics section of their manual has not been changed and they stand by it, as I quoted it earlier, and as expanded on in the archived thread.

Ray
 
The use of drift was a function of my getting in too big of a hurry when I posted on this thread. The chart uses the correct term, deflection. Good catch.
 
Vibe said:
I went and found the original discussion before posting here so I would understand the question. In the original scenario where there was crosswind between the bench at 100 yards and none afterwards then the bullet would most likely hit somewhere 10" from center at 1000 due to the now straightline path from 100 to 1000. Not exactly becasue the new path would be a tangent to the perviouly curved path. So long as the crosswind is constant from bench to target, the drift rate will increase. That same shot, were it measured at 50 yards would have been less than 1/2" off center.
Click to expand...

This is completely true. No more CLEAR, but true. :)

The bullet's path is curving in the crosswind, once the crosswind disappears it continues on straight like a flung sockfull of sand. It will impact less than 10 inches over. And yes this IS because it exits the crosswind "tangent to the previously curved path."

If the crosswind were to have continued for the full 1000yds the impact would have been considerably MORE than 10 inches.

al
 
Cheechako, that's why I try to use the term "wind drift" in quotes at least once :)

Regarding the Sierra explanations..... I think it's important to note that the verbiage is slight angle of attack relative to the bullet's flightpath. or "velocity vector."
 
FBecigneul said:
Wind effect on bullets by Alinwa and Cheechako--None, as I don't believe either makes bullets.
Click to expand...

FBike - You don't know if we do or if we don't. Make bullets, that is. Making wind is a nuther thing altogether. ;) ;)

Ray
 
Vern said:
if a bullet drifts/is pushed 1" at 100 yards is it pushed 10" at 1000 yards?
Click to expand...
I would think not..

That 1" doesn't represent MOA to 100yds, because the deflection in moa was changing throughout the entire 100yds. Every single yard of it including for example, moa of deflection from 90yds to 100yds, which could set the path toward 2 or 3moa of apparent error by 1000yds, with no further wind, yet hardly measure at that 100yd point.
So the 1" POI was just the result of continuous deflection occurring to that point(a curve), and not the same as a linear error over 100yds.
1" deflection at 100yds means huge 1000yd error(in MOA)

Well anyway, that's my view of it. And based on full value wind for the first 100yds.
 
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