Precision Long Range Shooting & the Coriolis Effect

You may not be taking this into Account in Precision Long Range Shooting. If you’re into long range shooting, its important to understand how the “Coriolis effect” affects your shot at 1000 yards or greater.

The Coriolis effect is the rotation of the earth and the movement of a target downrange from the shooter. This is another element that a long distance shooter has to consider for along with wind, rain, snow, distance, elevation and a many other factors. Accounting for all these factors signifies the skill sets needed for precision long range shooting.

In simple layman's term:
"if you're shooting West, your target’s gonna rotate up and towards us, which is gonna cause the bullets to hit lower."
"if you're facing east, the target's going to be dropping and slightly moving away, which is gonna cause the hits to be higher."

Jeremy from Gunwerks points out these small errors can cause huge misses at greater distances than 1000 yards if you don't pay attention to. Could be that buck that you're missing out on. See the video footage here.

The idea that Coriolis effect happens because the target is advancing or retreating on the horizon is absurd. That might explain what a shooter sees but there is no (Newtonian) physics to support it.

The vertical component of Coriolis effect stems from the fact that the rotation of the earth contributes just a tad of KE to any bullet launched in the same direction as the planet is rotating in, and subtracts just a little KE if fired against the direction of rotation. The slight difference in KE also means a slight difference of velocity at the muzzle, which means a slight difference in the time a bullet needs to cover a given distance. And bullet drop is a function of time of flight (32 feet/sec^2). So the bullet fired to the east will exhibit less drop than one fired to the west. Which is precisely why NASA fires all its rockets to the east. Why pass up a little free energy?

But that’s only the vertical component. Coriolis also has a horizontal component, which is totally dependent on the shooter’s latitude, completely INDEPENDENT of both the vertical component AND the azimuth of fire, and the change reverses direction depending whether you’re in the northern hemisphere or southern. All of which flies in the face of the article’s dumbed-down (and totally fallacious) explanation. Which probably is why he doesn’t bring up the topic of the horizontal component.

Too bad the guys who invented the Internet didn’t think to limit posting to people who’d passed a literacy test.

IMHO and based upon simple physics yes. That said I have seen and heard several arguments over the years, some of which got very heated, that it is not the same. Many believe that bullet spin drift comes into play more in one direction than the other. I am not a long range shooter anymore but I used to be and at my home range it just became part of the back round condition(s).

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