
Originally Posted by
Capebuffalo
The rotation of the Earth affects the path of bullet through the Coriolis effect. To experience a large Coriolis effect, a bullet needs to travel far, stays in flight long, and travels in a direction that is perpendicular to the axis of the earth’s rotation.
For distance and duration, the current record is held by Craig Harrison, who recorded a 2,475 m killing shot in 2009 during the War in Afghanistan. The bullet traveled for about 3 seconds before it hit the target.
The direction of Criag Harrison's shot was unlikely to be perpendicular to the axis of the earth rotation because Afghanistan’s latitude is only 30–40, and the target’s angle of elevation or depression is unlikely to be as large as 50–60 degrees.
So how much could the rotation of the earth affect Criag Harrison’s shot had he shot perpendicular to the earth’s axis? For simplicity lets assume he stood at north pole and shot horizontally, and that the bullet traveled for 3 seconds, landing 2.5 km away from the north pole. In this case, calculating the Coriolis effect is as simple as calculating how far the landing site that is 2.5 km away from the axis would rotate in 3 seconds:
2500 (m) * 0.000073 (arc/second) * 3 (second) = 0.55 (m)
Much less than the effect of wind.
Moreover, unlike the wind, which may change dramatically from time to time, the Coriolis effect is stable for a given bullet fight. A stable effect is easy to adjust for in the process of zero in.