Conditions Help
Typical values:

Standard: Alt 0, 59F, 10 MPH, 90 deg
Boomershoot: Alt 3000, 50F, 6 MPH, 90 deg
Barrow Alaska in February: Alt 10, -15F, 10 MPH, 90 deg
Denver in July: Alt 5280, 72F, 10 MPH, 90 deg

The "altitude" is really an air pressure measurement. A good approximation is the real altitude but for best results you should use an altimeter such as those sold in outdoor recreation and car accessory stores.

Use the temperature of the air the bullet will be traversing. A rule of thumb is that if your bullet is still above 1200 fps at the target a 10 degrees F error in temperature estimation will result in less than 0.5 MOA in impact estimation.

Good wind estimation (frequently called wind doping) separates the experts from the amateurs on the range. Use a wind gauge if you can but also pay attention to what the wind is doing down range. The first third to half of the bullet path is particularly important.

A wind coming straight toward the gun is at 0 degrees. A wind perpendicular to barrel from the right is 90 degrees and will result in a rightward adjustment to the scope. A wind perpendicular from the left is 270 degrees.

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