Hello everyone, I'm fairly new to the long range shooting deal, and have heard that the Coriolis is a semi big deal at 1000yds. Is it really a big deal, if so what range does it start to majorly effect the path of the bullet? Shoot a Rem700 in 30-06 with a 168gr SMK at 2850fps 10ft from the muzzle. I say "new", but I have shot out to 800yds, a few times at 500yds,and plan on shooting out to 1000yds soon.
At what range and beyond should I worry about the Coriolis effect?
- Thread starter oregon700
- Start date
It depends on what direction you're shooting. North, South, East, West? I understand the E/W effect, but I haven't been able to understand the N/S effect at different latitudes.
For the E/W effect, the bullet impact will be higher or lower depending on which direction you're shooting. It has to do with the earth rotating while the bullet is in the air. When shooting east, the target is moving away from you when the bullet is in the air, and when shooting west, the target is moving toward you when the bullet is in the air.
For the E/W effect, the bullet impact will be higher or lower depending on which direction you're shooting. It has to do with the earth rotating while the bullet is in the air. When shooting east, the target is moving away from you when the bullet is in the air, and when shooting west, the target is moving toward you when the bullet is in the air.
Too many other factors that will affect your shots to 1000 yards to worry about this.
When you do become proficient enough to use this adjustment I doubt that Mother Nature will ever give you conditions perfect enough for you to worry about calculating this into your shot.
When you do become proficient enough to use this adjustment I doubt that Mother Nature will ever give you conditions perfect enough for you to worry about calculating this into your shot.
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It is more of an issue in Florida than it is in Maine. The closer you get to the equator, the more you notice it.
This was a subject of great debate a couple of months ago and basically both sides mentioned here are right... but the further South you are, like I am, the more you will see the affects of it. In simple terms it is because you have more east-west distance between the same longitude measurements the further south you go till you hit the equator. (just wanted to add this for clarification) Think of a ball spinning, you have more surface distance that would pass a fixed, stationary line that extends north to south at the equatorial section than you have closer to the points of axis. This greater distance is what magnifies a more noticeable rise or drop when you shoot east or west he closer you get to the equator.
I maintain it is an important variable and I do compensate for it at long range but others further north maintain it is such a minor variable that it is not worth considering. And if you are in the northern states they are right.
This was a subject of great debate a couple of months ago and basically both sides mentioned here are right... but the further South you are, like I am, the more you will see the affects of it. In simple terms it is because you have more east-west distance between the same longitude measurements the further south you go till you hit the equator. (just wanted to add this for clarification) Think of a ball spinning, you have more surface distance that would pass a fixed, stationary line that extends north to south at the equatorial section than you have closer to the points of axis. This greater distance is what magnifies a more noticeable rise or drop when you shoot east or west he closer you get to the equator.
I maintain it is an important variable and I do compensate for it at long range but others further north maintain it is such a minor variable that it is not worth considering. And if you are in the northern states they are right.
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This is taken from an Army Chart using the military '06 Ammunition, A bit different then your ammo but it will give you an ideal.
Uncorrected drift is in feet.
1000 yards 1 ft
1200 yards 2 ft
1600 yards 6 ft
1800 yards 9 ft
2000 yards 12ft
2200 yards 17ft
Uncorrected drift is in feet.
1000 yards 1 ft
1200 yards 2 ft
1600 yards 6 ft
1800 yards 9 ft
2000 yards 12ft
2200 yards 17ft
I never would have guessed it would have that much effect or am I just missing the sarcasm?
Kraig's info is completely wrong, he is quoting old, out dated Spin Drift data not CE.
Generally speaking it's about 3" for a medium speed 308 and in the vertical plane not horizontal. Even that is subject to a host of caveats, and is more than likely something else and not CE.
We drag our atmosphere, that changes the value, most use the speed of the Earth from space and not the ground, as well we and the bullet start out attached to the Earth so we move too. The formulas used are wrong as they don't account for these variations.
Most ignore it and realize other factors matter more. I ignore it and hit just fine. Rarely do you ever hear of someone taking an azimuth to the target which is necessary. If it mattered every cardinal direction change would effect your zero. You'd never hit a UKD without a compass and computer.
Generally speaking it's about 3" for a medium speed 308 and in the vertical plane not horizontal. Even that is subject to a host of caveats, and is more than likely something else and not CE.
We drag our atmosphere, that changes the value, most use the speed of the Earth from space and not the ground, as well we and the bullet start out attached to the Earth so we move too. The formulas used are wrong as they don't account for these variations.
Most ignore it and realize other factors matter more. I ignore it and hit just fine. Rarely do you ever hear of someone taking an azimuth to the target which is necessary. If it mattered every cardinal direction change would effect your zero. You'd never hit a UKD without a compass and computer.
I really don't care if people agree or disagree with what I posted. Its factual, using the M1906 ammo (149 gr bullet w/a MV of 2700 FPS) during the period of WWI. Failing to take the drift into account would cause problems for example, when attempting to pin down a MG Nest while troops are assaulting 1000-2000 yards or more across no man's land.
The Ladder Sights on the US Krag, M1917, and M1903, (and others) took these corrections and built them into the sights for those respective rifles and Machine Guns of the period.
Re-read my post, I said it was only a guide, and the OPs ammo/rifle could be different.
I believe if one was to put the ammo into Litz's formula from Applied Ballistics for Long Range Shooting, you'll find its damn close.
Some people condemn slide rules, but we were able to hit the Moon using slide rules instead of computers.
The Ladder Sights on the US Krag, M1917, and M1903, (and others) took these corrections and built them into the sights for those respective rifles and Machine Guns of the period.
Re-read my post, I said it was only a guide, and the OPs ammo/rifle could be different.
I believe if one was to put the ammo into Litz's formula from Applied Ballistics for Long Range Shooting, you'll find its damn close.
Some people condemn slide rules, but we were able to hit the Moon using slide rules instead of computers.
Spin drift is different from Coriolis, the OP asked nothing about SD.
The fact you don't know the difference is scary when attempting to hand out advice.
If you want quotes, Pesja says is you just use a left hand twist barrel you cancel out the need to apply any drift values in the Northern a Hemisphere.
The fact you don't know the difference is scary when attempting to hand out advice.
If you want quotes, Pesja says is you just use a left hand twist barrel you cancel out the need to apply any drift values in the Northern a Hemisphere.
It's a small effect - a couple inches or so at 1000 yards. Moreover, it will be the same from shot to shot unless you're shooting 360 degrees, so it's tough to argue that it matters in the real world. As Lowlight says, we really ought to be shooting left hand twists in the northern hemisphere so that coriolis will partially cancel out the spin drift (which is larger, but still pretty small) - but we don't, because the deflections are small enough to ignore for most practical purposes. If you're trying to make first shot hits on beer cans at 1000 yards, think about it. Otherwise, not so much.
I shoot upside down to help.
more quotes,
From Canadian Manual:
B-GL-306-006/FP-001
FIELD ARTILLERY
VOLUME 6
BALLISTICS AND AMMUNITION
“In manual computations, rotational effects are not applied in Canadian gunnery procedures at ranges under 15000 metres, as the additional accuracy achieved does not justify the time expended.”
more quotes,
From Canadian Manual:
B-GL-306-006/FP-001
FIELD ARTILLERY
VOLUME 6
BALLISTICS AND AMMUNITION
“In manual computations, rotational effects are not applied in Canadian gunnery procedures at ranges under 15000 metres, as the additional accuracy achieved does not justify the time expended.”
That's the most assenine thing I've ever heard. You just mount the scope upside down. duh!
No - the horizontal deflection depends only on latitude. It goes right in the northern hemisphere, and drift follows twist. (right for right hand twist). The vertical deflection is what depends on direction.
Wouldn't it be different is you were close to the equator vs the north pole as the earth is spinning a lot faster at the equator than it is in the poles? I had to ask in case someone wants to hunt Prancer and Rudolf next year.
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