Spin drift and Coriolis at 1000+


Well-Known Member
Aug 22, 2012
Gotcha I was backwards east the POI is higher and west lower ;-)

Bullet bumper

Well-Known Member
May 20, 2009
Doesn't spin drift go up and to the right? And isn't the Coriolis affect the affect of the earth rotation on the POI? hence shooting east POI is lower and west its higher or do I have this backwards?
From the dim distant past I remember my training said that the Coriolis effect was worst if you were shooting north or south direction . If you shoot directly East or West the Earth and the target is moving in the same direction as the bullet well along the same line .
If you shoot North or South or angles in between the target moves along with the rotation of the Earth but the bullet is going sideways across that line of travel so at an extreme range it can miss the target.
In the Northern Hemisphere with a right twist barrel , spin drift and Coriolis add together. In the Southern Hemisphere one subtracts from the other in a right twist barrel.
That's why we are such great shots down here :D
I could be remembering wrong so I am happy to be corrected.


Well-Known Member
Jan 31, 2005
Searcy, Arkansas
Applied Ballistics, as well as BulletFlight and Shooter apps are all available at the google play store. I have all three loaded on my Droid. Any one will do both spin drift and coriolis.


Well-Known Member
Jan 21, 2007
So if I understand this properly, you add sd to a left wind and you subtract it from a right wind?


Well-Known Member
Oct 31, 2009
Thunder Basin, WY
Would be nice to have left twist barrels to offset some of the CE, but then if we did that; we'd probably need left thread actions too.......last thing we need is the barrel backing out of the action when it torques from bullet launch.:rolleyes:


Well-Known Member
Feb 5, 2012
But I only employ the coriolis to be part of shots beyond 1200 yards as the effects are usually small before that.
So, at 800-1000 yards, you would not worry about SD and coriolis?

I ask because I just set up a range for 1100 yards and it is 208 degrees SW. I've only shot at 606 yards and I want to do all the work possible before I jump to 800 (then 1000 yards). I'm not finding a lot of material on the subject and this video has me concerned for 1,000 yards.

[ame=http://www.youtube.com/watch?v=jX7dcl_ERNs&list=FLYs3czMz3TnUvdu9ylBxMxg]Demonstrating how Coriolis effects bullet drop at 1000 yards - YouTube[/ame]


Well-Known Member
Feb 9, 2010
So what would be "just" the Coriolis effect if the target is North or South at 1000 yds?


Well-Known Member
Oct 1, 2007
I was tinkering around with my shooter app today...punching in different senarieos.

300 gr Hybrid at 1500 yards...49th paralell shooting 4 diff directions with zero wind. All other parametes the same. Dialups as follows...

shooting at 0 Degrees (north) 113.7 up, .9 left
90 degrees...(east) 112.7 up .9 left
180 degrees (south) 113.7 up .9 left
270 degrees (west) 114.7 up .9 left

So this thing is telling me that in an east west situation I don't have any hoazontal (windage) coriolis?? Zero effect no matter which direction i shoot!!!!

That can't be right. I have to assume that the .9 is the spin drift...which should remain constant at a givin distance. I have the coriolis box checked on the app...I triple checked that.

What gives???


Well-Known Member
Feb 1, 2009
Agree with what Broz says. Typically depending on rifle and BC etc at 1000 yds with a right twist barrel the poi is 6" right and north or south adds 3" right so for my poi for my .375 /408 hunting rifle I set it up to shoot about 1 moa left at 300 yds. When you get out to 2000 yds you have to correct more. For shooting east poi is higher and west lower. Think of it as shooting from on a giant spinning giant globe.

Recent Posts

Latest Classifieds

Nightforce has great tracking capabilities, they are rugged, a bunch of elevation, holds zero forever, and reticles are designed for long range shooting. So if you are looking to shoot long distances constantly, then you need a scope that can take the abuse. -- gilmillan1

Culture Of Excellence At Nightforce Optics
By Len Backus

A high level of quality both in production and in service. Read More

Nightforce is such a solid combo of reticle, available elevation, glass that is good enough to shoot at the longest range you can dial. Nightforce has bullet proof construction that can handle the incidental horse rolling or some other rodeo action. -- bigngreen

Nightforce ATACR Scope Review
By Jeff Brozovich

The new NightForce ATACR is for sure a top choice for any long range shooter. Read More

The total package. Nightforce is the best I have used as far as turret feel and solid detents. I have never had one that didn't track right on and always return to zero. Nightforce NXS is the best value for everything I need. -- Broz

Nightforce Velocity 1000 Reticle Review
By Scott Shreve

I think Nightforce knocked it outta the park with this reticle! Read More