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Posted: 6/22/2017 10:22:15 AM EDT
[#1]
Quote HistoryQuoted:
It may be discussed out of context at times, but it is absolutely a thing. It doesn't affect aircraft (or anything else that is guided) because aircraft can make course corrections mid-flight, while a bullet cannot. Quote HistoryQuoted:
Quoted:
The Coriolis effect is bullshit. If it can affect bullet path then it should also affect airplanes and helicopters even more profoundly...which it does not. It doesn't affect aircraft (or anything else that is guided) because aircraft can make course corrections mid-flight, while a bullet cannot. |
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Posted: 6/22/2017 10:23:20 AM EDT
[#2]
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The Coriolis effect is bullshit. If it can affect bullet path then it should also affect airplanes and helicopters even more profoundly...which it does not. |
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Posted: 6/22/2017 10:24:21 AM EDT
[#3]
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Yes. It's been tested. Don't remember what caliber, maybe 7 mag. Guy set up so he could fire 1000 yards east and from the same spot 1000 yards west. Point of impact was (I think) about 1- 1.5 feet difference in elevation. I remember seeing his video of it. |
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Posted: 6/22/2017 10:32:26 AM EDT
[#4]
physics and Arfcom...
a lost cause |
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Posted: 6/22/2017 10:33:33 AM EDT
[#5]
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It does have effect. Ever seen how long it takes to fly to Japan from the US then from Japan to the US one will take longer than the other for the same distance(assuming flying from say LA to Tokyo following the same path both ways. Why also do you think they fly over the poles instead of a straight line for long flights across the globe. High altitude bombers figured that out in the pacific in WW2 |
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Posted: 6/22/2017 10:43:13 AM EDT
[#6]
Multiples here with only direction of fire changed and one in the southern hemisphere.
@RDTCU  Attached File Attached File Attached File Attached File |
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Posted: 6/22/2017 11:05:09 AM EDT
[#7]
Question for everyone saying it doesn't matter.
How many of you have shot at or past 1000 yards? If so do you do it often enough in enough locations that you are shooting at different compass headings much less closer/further to the equator? I'm thinking if one just shoots at one location and figures out their dope then they're dialed in for that location and Coriolis effect "doesn't matter". If your home range was in New Hampshire shooting northeast in zero wind and then you go to a range in Southern California shooting southwest in the same mythical no wind conditions you'd probably scratch your head and wonder how your 1000 yard zero changed by a foot or two. You'd re-zero your scope for SoCal and when you got home you'd need to re-zero again and theorize that the scope must have a zero shift from the airline travel. |
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Posted: 6/22/2017 11:27:54 AM EDT
[#8]
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The coriolis effect is negligible over the time it takes a bullet to travel 2 miles. |
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Posted: 6/22/2017 11:29:16 AM EDT
[#9]
Quote HistoryQuoted:
Question for everyone saying it doesn't matter. How many of you have shot at or past 1000 yards? If so do you do it often enough in enough locations that you are shooting at different compass headings much less closer/further to the equator? I'm thinking if one just shoots at one location and figures out their dope then they're dialed in for that location and Coriolis effect "doesn't matter". If your home range was in New Hampshire shooting northeast in zero wind and then you go to a range in Southern California shooting southwest in the same mythical no wind conditions you'd probably scratch your head and wonder how your 1000 yard zero changed by a foot or two. You'd re-zero your scope for SoCal and when you got home you'd need to re-zero again and theorize that the scope must have a zero shift from the airline travel. Wind and mirage. Wall of text won't get you a hit at 1K or beyond. Keep in mind you pose this question to people who don't even own a rifle, or who have a safe queen they won't fire because brass might mark up the deflector nubb. |
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Posted: 6/22/2017 11:47:56 AM EDT
[#10]
Quote HistoryQuoted:
Multiples here with only direction of fire changed and one in the southern hemisphere. @RDTCU https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236370.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236372.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236374.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236375.JPG I figure the TAC-50 has a 1-15 or 1-20 twist to minimize spin drift, and people shooting them close say they shoot loose, which suggests a slow Rate of twist as a trade off for long range consistency. |
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Posted: 6/22/2017 11:51:15 AM EDT
[#11]
Quote HistoryQuoted:
Wind and mirage. Wall of text won't get you a hit at 1K or beyond. Yep coriolis is only a small amount not worth considering by itself for 1k, not even enough to dial for, but this thread is specifically about coriolis over extreme long range so we are discussing it. |
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Posted: 6/22/2017 12:03:28 PM EDT
[#12]
Quote HistoryQuoted:
Multiples here with only direction of fire changed and one in the southern hemisphere. @RDTCU https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236370.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236372.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236374.JPG https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-09-236375.JPG |
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Posted: 6/22/2017 12:09:13 PM EDT
[#13]
Quote HistoryQuoted:
To satisfy my curiosity, take wind to zero for all cases and see what it shows. 
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Posted: 6/22/2017 12:15:37 PM EDT
[#14]
I think the layman has heard "spin drift" and, having no idea what it actually is, decided it was the same as the Coriolis effect.
Sure, the Coriolis effect exists and is a factor on extremely long range shots, but it is massively blown out of proportion compared to much more important factors like spin drift, mirage, wind, etc. It just sounds more impressive to the uninitiated to say "he had to account for the rotation of the earth!!" instead of "he actually had to read the mirage caused by heat to determine wind speed and, at that distance, seeing a human-sized target through mirage is like trying to read a speed limit sign at 100 yards through a rain soaked windshield." |
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Posted: 6/22/2017 12:21:26 PM EDT
[#15]
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Hitting someone at 3500 yards with a firearm is more luck than skill, IIRC, the last American sniper record holder has said as much. |
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Posted: 6/22/2017 12:30:30 PM EDT
[#16]
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If you mag dump 5 mags and get one hit, does that count? At 2 miles you aren't really concerned about react to sniper drills. |
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Posted: 6/22/2017 12:46:50 PM EDT
[#17]
Quote HistoryQuoted:
To satisfy my curiosity, take wind to zero for all cases and see what it shows. Here is a pic of one with no wind. The others are all the same as I already posted minus wind drift and AJ.  Attached File |
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Posted: 6/22/2017 12:51:43 PM EDT
[#18]
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It changed nothing but aerodynamic jump, which is from direction and speed of air moving across the bullet and bbl twist direction and rate. Here is a pic of one with no wind. The others are all the same as I already posted minus wind drift and AJ. https://www.AR15.Com/media/mediaFiles/83091/2017-06-22-11-236441.JPG |
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Posted: 6/22/2017 1:03:36 PM EDT
[#19]
Is the 'Coriolis drop' in the calculator really Coriolis? or is it the Eotvos Effect?
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Posted: 6/22/2017 1:07:11 PM EDT
[#20]
Quote HistoryQuoted:
Is the 'Coriolis drop' in the calculator really Coriolis? or is it the Eotvos Effect? |
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Posted: 6/22/2017 1:08:02 PM EDT
[#21]
Quote HistoryQuoted:
Is the 'Coriolis drop' in the calculator really Coriolis? or is it the Eotvos Effect? |
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Posted: 6/22/2017 1:14:54 PM EDT
[#22]
Quote HistoryQuoted:
Interesting that horizontal C drift is independent of target direction... |
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Posted: 6/22/2017 1:20:38 PM EDT
[#23]
Quote HistoryQuoted:
Is the 'Coriolis drop' in the calculator really Coriolis? or is it the Eotvos Effect?  Attached File |
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Posted: 6/22/2017 1:28:27 PM EDT
[#24]
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Posted: 6/22/2017 1:30:44 PM EDT
[#25]
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Can anyone explain why that is? I'm having trouble conceptualizing it. |
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Posted: 6/22/2017 1:32:23 PM EDT
[#26]
Quote HistoryQuoted:
Why also do you think they fly over the poles instead of a straight line for long flights across the globe. |
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Posted: 6/22/2017 1:39:18 PM EDT
[#27]
Quote History |
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Posted: 6/22/2017 1:45:44 PM EDT
[#28]
Quote History |
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Posted: 6/22/2017 1:57:33 PM EDT
[#29]
Quote HistoryQuoted:
Are you being nitpicky about the name? Because it would be substantia(for hitting a small target)l over a two mile flight time. N27° lat, 27inHg, 90°, 250otm@2900fps, 8.4sec flight time Firing north = 35" drift right drop zero" Firing south= 35" drift right drop zero" Firing east = 35" drift right drop 115" Firing west =35" drift right 115" high S27° lat all the drift will be to the left. In less dense air all the numbers will be reduced because flight time is shorter. |
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Posted: 6/22/2017 2:02:51 PM EDT
[#30]
Quote HistoryQuoted:
physics and Arfcom... a lost cause When I was in engineering school, they taught Coriolils effects. plus, Rex explains it fairly well here. https://www.youtube.com/watch?v=hiRaP8qxqa4 But basically, under 1,000 yards you've got bigger factors to worry about. |
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Posted: 6/22/2017 2:45:48 PM EDT
[#31]
Fun fact: airplanes don't really "fly", they hover and the earth just spins under it.
Also, the SR-71 was so fast cause it could hover more still. |
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Posted: 6/22/2017 3:20:02 PM EDT
[#32]
Quote HistoryQuoted:
Keep in mind you pose this question to people who don't even own a rifle, or who have a safe queen they won't fire because brass might mark up the deflector nubb.  . Ain't that the truth.
I'm a total newb to trying 1000 but know the ballistic apps at 1K change the solution when you check "account for coriolis" on or off. The first video posted demonstrates a minute plus of elevation difference at 1K and because of flight time it gets a lot worse further out. Is it the only or biggest concern? Of course not but it has enough effect that it should be factored in for ELR shooting. I'd imagine in real world examples it will help you get closer to a first round hit so you don't have to make as big of a correction after your first round miss. |
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Posted: 6/22/2017 4:06:23 PM EDT
[#33]
omega x omega x R
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Posted: 6/22/2017 4:11:19 PM EDT
[#34]
Quote HistoryQuoted:
The Coriolis effect is bullshit. If it can affect bullet path then it should also affect airplanes and helicopters even more profoundly...which it does not. |
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Posted: 6/22/2017 4:20:52 PM EDT
[#35]
Quote HistoryQuoted:
Uhhhhhh... yeah, it does. Aircraft can make corrections for it on the fly however. |
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Posted: 6/22/2017 4:21:14 PM EDT
[#36]
At the distances it takes to notice coriolis if your wind call is off a mph or two it will have twice the effect of coriolis. I shoot at 100 yards sometimes out to 300 off a bench in only the best weather for 3 shot groups so needless to say I'm kinda a expert.
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Posted: 6/22/2017 4:22:32 PM EDT
[#37]
So the Coriolis effect or the north south version(evector effect?),while minor at ranges under 1000 is a constant variable, unchanging once calculated for a position/target combo, like bullet drop for a particular load/range/air density on a given day. sure it will change tomorrow with a new target and shooting position but if you can calculate it before hand, plug it into the scope and eliminate one negative variable who wouldn't? I can't see a reason NOT to have it unless you are super crunched for time(in which case I would recommend against taking 3450 yard shots...),
If i'm completely off base please correct me because I have only the briefest grasp on this. |
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Posted: 6/22/2017 4:24:48 PM EDT
[#38]
Quote HistoryQuoted:
The Coriolis effect is bullshit. If it can affect bullet path then it should also affect airplanes and helicopters even more profoundly...which it does not. |
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Posted: 6/22/2017 4:28:13 PM EDT
[#39]
Quote HistoryQuoted:
How much does the planets rotation really effect things? An Airplane doesn't ADD its speed with Earth's rotation. Like flying in the opposite direction, a commercial jet going 500 mph, doesn't cover more distance even though its not bolted to the Earth. It doesn't add 1,000 mph that the Earth is supposedly turning under it. Plus, in your car, as you drive 70-80 mph, a Fly buzzing around doesn't splat into the back of your car's windshield. When it decides to fly after already accelerating while it was resting. you at the center are aiming for the person. if the targeted person looks down at the disk, the edge will be screaming by at 188 miles per hour. 3.14 miles per minute. you would essentially have to "lead" the target as if they were traveling almost 200mph. The bullet goes on a straight line once it leaves your barrel. almost the same concept, except in application the earth is spherical which adds other fun. edit: you are elevated over the center (not rotating) and the person is standing on the edge of the disk (moving). |
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Posted: 6/22/2017 4:35:55 PM EDT
[#40]
Quote HistoryQuoted:
So the Coriolis effect or the north south version(evector effect?),while minor at ranges under 1000 is a constant variable, unchanging once calculated for a position/target combo, like bullet drop for a particular load/range/air density on a given day. sure it will change tomorrow with a new target and shooting position but if you can calculate it before hand, plug it into the scope and eliminate one negative variable who wouldn't? I can't see a reason NOT to have it unless you are super crunched for time(in which case I would recommend against taking 3450 yard shots...), If i'm completely off base please correct me because I have only the briefest grasp on this. Gravity, Coriolis, spin drift, humidity, air temp, pressure, angle of fire, muzzle velocity, BC, distance, scope tracking error, height over bore, zero distance, zero offset, these can all be measured and used in calculating a firing solution in a solver. All that is left is a wind(a huge one), muzzle velocity extreme spread and shooter error. Obviously there is a limit to the accuracy of your data but do your best. |
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Posted: 6/22/2017 6:28:33 PM EDT
[#41]
Quote HistoryQuoted:
The Coriolis effect is bullshit. If it can affect bullet path then it should also affect airplanes and helicopters even more profoundly...which it does not. |
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Posted: 6/22/2017 6:35:19 PM EDT
[#42]
Don Coriolis?
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Posted: 6/22/2017 6:40:05 PM EDT
[#43]
... only mildly surprising how many ARFCOM posters are ignorant to natural sciences
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Posted: 6/23/2017 12:15:33 AM EDT
[#44]
Quote HistoryQuoted:
round disk If you picture the northern hemisphere as a flat plate, the north pole is the center of the plate and the axis it rotates about, while the edge of the plate is the equator. Place the "shooter" at any point on the plate, and the "target" as any other spot on the plate. Visualize the path the bullet would travel to hit the target. Then spin the plate counter-clockwise and trace the path the bullet would travel (which is independent of the plate itself) and you'll see that the bullet always ends up right of the target. This confirms the direction of fire is independent of the drift direction. |
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Posted: 6/23/2017 7:37:13 AM EDT
[#45]
Quote HistoryQuoted:
They do that because it's a shorter distance. Quote HistoryQuoted:
Quoted:
Why also do you think they fly over the poles instead of a straight line for long flights across the globe. If there is anything ARFcom understands, it's equations of motion. |
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Posted: 6/23/2017 8:08:17 AM EDT
[#46]
During WWI the Germans built a large gun called Big Bertha. It was built to shell Paris which was 70 miles south of it. When working out the ballistics of the shot they calculated that they would have to lead the city by 1 mile due to the speed of the earth's rotation at that latitude. Too bad this guy wasn't still alive. He lived and breathed ballistics and would keep gunnery officers up all night working out ballistics solutions to various scenarios.
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Posted: 6/23/2017 9:00:08 AM EDT
[#47]
Quote HistoryQuoted:
I understand it now! I understand why the horizontal drift is always in the same direction. If you picture the northern hemisphere as a flat plate, the north pole is the center of the plate and the axis it rotates about, while the edge of the plate is the equator. Place the "shooter" at any point on the plate, and the "target" as any other spot on the plate. Visualize the path the bullet would travel to hit the target. Then spin the plate counter-clockwise and trace the path the bullet would travel (which is independent of the plate itself) and you'll see that the bullet always ends up right of the target. This confirms the direction of fire is independent of the drift direction. 
That also explains why the horizontal component of the effect is highest at the poles and zero at the equator... |
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Posted: 6/27/2017 10:27:43 AM EDT
[#48]
Just watched this vid on the Canadian's record shot. https://www.youtube.com/watch?v=bzwY6jIwr2o
Must have used a custom angled scope mount? Over 800' holdover? 
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