Reading The Wind by Shawn Carlock

[Shawn Carlock]

Lorenzo,

I use the Nightforce Exbal program.

[Shawn Carlock]

No it just applies to everyone who hunts in canyon country. Most people just never think about waht happens when the wind blows over certain terrain features. Good luck hunting.

[Ari]

Hi Shawn,
I have a question about your article:

"When shooting a righthand twist barreled rifle, a left to right wind will cause the bullet to impact to the right and slightly low. The same barrel in a right to left wind will cause an impact to the left and slightly high."

could you explain me why this happen?

Best regards.

Ari.

[Shawn Carlock]

There is a named effect for this action but the name escapes me right now. By belief is this, when a bullet is engraved by the rifle barrel it makes places for the air to grab the bullet and effect it. With this in mind spinning into a wind causes it to strike slightly low and spinning with it makes it strike slightly high. This effect is very small but does exist. I have noticed that poly rifling and 5r rifling engrave the bullet less and tend to not have an abrupt edge in the engraving. Bullets fired through these barrels show less of this effect in the same conditions. Reguardless of why, it does occur. it is very noticable with more accurate smaller caliber rifles like a 6mm BR benchrest rifle that shoots "in the 1's" it is very noticable. The accuracy of this rifle and size of its bullets make the .100-.150" elevation change of this effect very noticable. If you are shooting a 1/2" .338 cal rifle it is tougher to see, but does exist. Hope this helps.

[gamedog]

Great article Shawn. One question . This weekend I missed a shot at a coyote @ 288 yards strait across a draw. I'm shooting 180 gr TSX"S @ 3200 fps. I had a solid 20 mph headwind and thought that would drop the bullet a bit. So I aimed at the top of his back. Do you believe the headwind lifted the bullet or dropped it? I understand cross winds , but this has be baffled.

[Shawn Carlock]

If you had a 20 headwind shooting across a draw you probably shot over it but it is hard to say for sure without seeing the conditions and location of the shot.

[Ari]

Hi again Shawn,

It´s possible that the name of this effect would be "Magnuss effect"?
May be that this effect works in the other way?:

"When shooting a righthand twist barreled rifle, a left to right wind will cause the bullet to impact to the right and slightly HIGH. The same barrel in a right to left wind will cause an impact to the left and slightly LOW."

Best regards.

Ari.