Posted on 12/02/2019 5:17:30 AM PST by w1n1
Excellent travel tip! ;-)
Actually when shooting North or South the target is moving East. The target is always moving towards the East. You should say that when shooting North the target is moving to your right. And when shooting South the target is is moving to your left.
Now when shooting NW, NE, SW or SE, I don’t know....
Never mind...
You’re moving to the east, as well, so the target to the north is moving less than you are. However, my experience is with Coriolis acceleration, not shooting, so I’ll defer to shooting experts on targets.
With a flight time of just over one second for a .308 at 1000 yards, the effect should be minimal to negligible to irrelevant, unless an inch or so one way or t’other matters...
Funny, for all the time I’ve spent researching & calculating long-range shooting, and all the references to Coriolis Effect I’ve seen, I don’t recall ever actually seeing a quantitative reference to it (a la “.308 at 1000m aiming due south, add 3cm left”).
Holdover, windage, velocity, etc discussions always mention numbers at some point. “But muh Coriolis!” doesn’t.
Thanks, western Canadian infantry training stuck in the head heh.
I suppose a picky sniper who enjoys mock self criticism might smirk at calling a head shot “a miss” shooting North at a terr, because point of aim was center of cranio-occipital cavity (between the eyes) and instead bullet struck left orbit...
All from failure to take Coriolis Effect into account...Tsk, tsk...At 1000 yds, I’ll count that a hit...Red mist is red mist!
Artillery, and mortars, absolutely yes. But there is no measurable distance in the time of flight that takes for a rifle round
Artillery, and mortars, absolutely yes. But there is no measurable distance in the time of flight that takes for a rifle round
i’ll just sneak up on him in the dark and club him with the butt of my rifle... and see which way he spins to the ground...
That’s because unlike wind, angle or air pressure variations, Coriolis depends on both firer and target location on the earths surface and direction of fire....
It has varying effect from pole to equator and the declination angle of fire itself drives the equation.
And never have I seen anyone address it as a value large enough to matter.
Well, I would like to, but how do I get the Antelope to the moon?
Oh, do I need a hunting license for that?
They use GPS, also use it to pull density altitude, wind speed etc. They are pretty sophisticated.
I never even bother setting mine to adjust for coriolis effect it’s negligible
>>if you were somewhere in the northern hemisphere, the points south of your are moving east at a slightly faster speed than you are, and points north of you are moving east slightly slower that you are. Does that make sense?<<
Wouldn’t my rifle’s muzzle be traveling east at a faster rate than my rifle’s chamber?
To some infinitesimal amount, possibly. It depends on how far the chamber is from the Earth rotation axis as compared to how far the muzzle was from the Earth rotation axis. I presume my post was fairly understandable and your question is just poking fun. But if not, let me know.
No, no “poking fun” intended. This is scientific discourse. If in the northern hemisphere shooting south, as you say, the target is moving east faster than the rifle. however, the rifle’s muzzle is moving east faster than its chamber. Therefore it seems that the barrel movement would offset any need for aim compensation.
Its a bit harder, even for me, to try to analyze the what may be occurring in the internal ballistics compared to once the bullet has left the barrel and is its own entity.
I suspect it doesn’t matter that the muzzle is traveling at some infinitely smaller amount faster than the chamber. The southern target is still traveling east faster than the muzzle at the moment the bullet exits, so there is still an uncompensated difference in eastward velocity between exit and impact points.
I’m going to stick to my story. Instinctively I thought that your explanation did not cover the subject, but I wasn’t sure why. So I thought of an illustrative experiment. You have to disregard bullet acceleration and deceleration like we have been doing.
Consider Earth to consist of a two dimensional disc at real earth’s equator. You shoot at a target toward the outside of the disc. The target is traveling at a faster velocity eastward than your muzzle end. However, that’s not what matters. It matters that the target and muzzle are traveling at the same angular velocity eastward.
The bullet sweeps out a straight line as it travels from the chamber toward the target. It would have to sweep out a curved line in order for you to have to lead the target in aiming. This guy draws the same conclusion toward the end of his video.
https://www.youtube.com/watch?v=jX7dcl_ERNs
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