Spin and Coriolis Drift

Discussion in 'General Rifle Discussion' started by Trez, May 9, 2012.

  1. Trez

    Trez Well-Known Member

  2. ZeusEcho

    ZeusEcho Member Lifetime Supporter

    Great article thanks!

  3. locutus

    locutus Well-Known Member Supporter

    This is very interesting.

    It's "built in" to the artillery firing tables, but this is the first time I've seen mention of it for small arms.

    I would imagine it's covered fairly thoroughly at the sniper schools, especially now that the .338 LaPua and .50 BMG have gained so much popularity with snipers.
  4. billt

    billt New Member

    While both effect a bullet, 95% of most shooters don't shoot at long enough ranges for it to be enough of a concern. Also the Coriolis Effect varies depending where on the planet you happen to be shooting. It is the force that makes a hurricane spin. It is opposite in the southern latitudes than it is in the northern latitudes. It also changes if you are shooting north to south, or east to west. Wind and the ability to calculate precise ranges will effect the outcome of a shot far more than either spin drift or Coriolis Effect will.
  5. Shoobee

    Shoobee New Member

    More like 99.999999% of all shooters are not affected by the Earth's spin.

    This is a rocketry and missilery issue.

    I don't know of any long range snipers who make their marks with one shot either, they instead normally correct off their spot for their first shot. That's why they have a spotter.

    It is however fascinating to note that having your rifle range point due north, the best direction to keep the sun out of your eyes, but the worst direction for taking into account the rotation of the Earth, impacts your data for 1000 to 2000 yard shooting with your 40 or 50 cal Barrett.

    My longest shot is 425 yards on a buck that was moving up a ridge from south to north. My rifle was set for 250 yards. I had a clear view of his head, neck, spine, and tail as he hiked uphill casually away from all the dirt spouts my buddies were creating by wasting their ammo on him. I aimed for his head, and I hit him in the spine just above his tailbone with one 200 grain bullet from my .338 at the time.

    The hydrostatic shock of the impact nailed him as much as anything else. We spent the rest of that day gutting, skinning, quartering (there were 4 of us in the group plus one lady as well), and hauling out the carcass. It was a good day, thanks to a Remington 700.

    Did not have to worry about rotation of the earth. But then luckily for me the buck was heading due north, and our rifle range was positioned due north as always as well.

    I think elevation and temperature are more significant than rotation of the Earth in terms of affect on data and setting.
    Last edited: May 10, 2012
  6. primer1

    primer1 Well-Known Member Supporter

    Dirt spouts from buddies wasting ammo on a deer? Does the term "ethical hunting" have any merit in your neck of the woods? Sheesh.