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Wind affect on bullets
jesheba
Member Posts: 102 ✭✭
Just returned from a South Dakota Prairie Dog shoot.On one of our days my partner and I had experienced unexpected affects of the wind on some of our shots taken at 200 to 350 yards.The wind was from our right and somewhat behind us.We guessed the velocity to be between 10 to 15 mph.We both were shooting 22/250 rifles (50 grain bullets).Simply holding to the right a few inches was putting us on the mark in most cases but now and then we would find our shots 3 to 6 inces high!We could only assume the wind was causing this affect?We have been shooting dogs for 12 years and don't recall having experiencing this in the past.Can a wind affect the elevation of a bullet's path?
Comments
If you are flying a plane and have a tail wind, you get there sooner.
Bullet drop by gravity depends on how long it is in the air, between the gun and the target. If it is in the air for a shorter length of time, the drop will be less.
NOW, 3 to 6 inches high at 350 yards was NOT DUE TO THE WIND.
A 5 mi/hr wind is about 7 ft/sec. A change in bullet speed of 7 fps on a 22/250 that is zipping along would have NO measureable affect on bullet travel time, or change in vertical point of impact.
IMHO your change in vertical poi was from something else.
You still had a great time, right ?
My answer will depend on how much detail you would like to have on this subject. Most folks like to get the jist of the idea and then let it go while others like to get all the detail and science they can find.
It is a portion of what is called the Magnus Effect. The simple answer is this:
When a bullet is fired from a barrel with a right hand twist and the wind is from the right but slightly behind the shooter, the bullet will seek to the left and RISE slightly due to lessening of pressure surrounding the bullet. Essentially, the bullet will fly slightly faster due to lower pressure, arrive at the target slightly faster and the impact will be located to the left and slightly higher from a point of aim.
Conversely, if the wind is from the left and slightly behind the shooter, the pressure surrounding the bullet is higher, so the bullet seeks to the right and strikes slightly lower.
Imagine the proverbial clock face parallel to the ground. In the first case, wind from let's say 3 o'clock, the bullet will strike at approximately 10 o'clock. In the other scenario, wind from 9 o'clock will result in a 4 o'clock strike.
The shift of the wind from left or right to being slightly behind the shooter serves to increase the effect slightly.
Two things to bear in mind:
These effects are almost indistinguishable at ranges under 200 yards unless the winds are high. As the distance increases the effects increase.
Wind can change both direction and force at different distances. That's why point blank benchrest shooters use so many flags. They attempt to judge what impact the wind will have on the bullet based on the aggregate of the directions and force of the wind at the various distances.
There is a lot more to this both from the standpoint of ballistics and the physics of flight. If you want to inderstand this and the other effects on bullets I suggest that you read "How Do Bullets Fly":
http://www.nennstiel-ruprecht.de/bullfly/
Best.