The home of Shooting Times and Sporting Gun

Should I worry about the Coriolis Effect, what is it?

Mike George
This is a natural phenomenon brought about by the spin of the earth, causing moving objects like bullets to deviate slightly to the right when fired in the Northern Hemisphere, and to the left when fired in the Southern.

The mathematics of it are extremely complex (to me, anyway), and to compensate for it you have to know the position (in terms of degrees of latitude) from which the shot is fired, and, I believe, the direction of the shot.

Is it worth bothering about?

Well, if you are firing a large naval gun or land-based artillery piece at a target several miles away, it certainly is.

But if you are shooting a fox, say at a couple of hundred yards or even more, then it isn?t because the deviation is so tiny.

If, as a rifleman, you are going to get worried about Coriolis Effect, then first consider other factors which can affect a bullet?s flight.

The most significant is wind, while ballistic performance is also affected to a very small degree by atmospheric pressure and humidity.

Aim can be affected by the bending of light caused by its passing through small thermal currents.

There are also inconsistencies in ammunition which can cause shots to go high or low.

You can add personal problems to these factors, such as slight vision problems, shaky muscles caused by cold, and an inability to judge range.

You may think that, one way or another, it is a miracle we hit anything at all ? yet we do!

I wouldn?t worry about the Coriolis Effect if I were you.