A Question For You Loooonnnggg Range Shooters

[Paul Cat]

Can someone settle a pub discussion for me? Do long range shooters allow for the Coriolis Effect?

[That bald headed Geordie]

I shoot up to 1000 yards and coriolis is not something I even think about.   Wind has the biggest effect on any bullet at any distance.

If however you are shooting an artillery piece at very long range (many miles/kilometers) then depending on the direction of your shot (north, south, east and west) then I believe it has to be taken seriously and factored in your elevation/windage etc. 

But for rifle shooting it is the least factor to worry about.   That is just my opinion.

 

 

[Paul Cat]

Thanks for that.

I imagined that IF it were possible to shoot over the ranges you do in nil wind )how often does that happen?) then CF might be a factor but it would be so minor that in the real world, with even a light wind, the latter would be vastly more influential.

[Avian]

Yes I take it into account, why would you not?

Ballistic calculators can do this so why would one not allow for it for long range stuff.  Yes wind is a more important factor but every little helps

 

[maximus otter]

l use Strelok Pro which includes the Coriolis Effect (also spin drift, vertical shift due to crosswind, etc.) Set up once, then “fire & forget”.

maximus otter

[No i deer]

I watch a video on YouTube where a test was carried out which was to fire shots to 1000yd target then at 1000yds in the opposite direction,one going against the direction of the earth rotation and one with the earths the rotation.possibly east and west.

There was about 6 inches difference either way from poi  from the rifle zeroed in a different direction. A version of something like that 😁

[brown dog]

Attached Litz's piece on it.

The effects of coriolis vary according to both latitude and bearing of fire.

The effects are deterministic (ie you can quantify them with certainty) and make sense to include if your shooting discipline doesn't allow you sighters. But, with sighters allowed, coriolis is a layer of detail that, as others said earlier, is probably not worth bothering with.😊

ABDOC108_GyroscopicAndCoriolis.pdf

[TJC]

It has no discernible impact in shooting sports.  

[Popsbengo]

2 hours ago, brown dog said:

The effects are deterministic (ie you can quantify them with certainty) and make sense to include if your shooting discipline doesn't allow you sighters. But, with sighters allowed, coriolis is a layer of detail that, as others said earlier, is probably not worth bothering with.😊

ABDOC108_GyroscopicAndCoriolis.pdf

Sighters will include all factors, and as mentioned earlier,  wind will play the greatest role.  My view is, as coriolis effects are deterministic and are easy to apply with a ballistic app, why not account for it as it's a fixed offset?  It's small if your shooting at a mile in a roughly North East direction but calculable.  .338LM 300gn 2900 f/s mv  at 1760yds on a track of 340deg = left 0.2mil.

Interestingly spin drift is greater.   For the firing solution above add in spin drift (r.h) and it's left 0.7mil (0.5 spin + 0.2 cor.).  If I add a 5mph westerly - it's 2.0 Mil.  Wind rules OK 😁

[TJC]

28 minutes ago, Popsbengo said:

My view is, as coriolis effects are deterministic and are easy to apply with a ballistic app, why not account for it

You shouldn’t account for it because ballistic apps grossly over-calculate the impact. That is why most shooters turn off the coriolis calculation on their Kestrels. 

[Popsbengo]

1 hour ago, TJC said:

You shouldn’t account for it because ballistic apps grossly over-calculate the impact. That is why most shooters turn off the coriolis calculation on their Kestrels. 

Says who?  I can't find any supporting evidence for your view, could you point me please as I'm quite interested?

[TJC]

10 minutes ago, Popsbengo said:

Says who?  I can't find any supporting evidence for your view, could you point me please as I'm quite interested?

Says most of the leading precision rifle instructors and top competitors. It’s actually common knowledge that most turn off this feature. Attend any high quality course and this topic comes up time and again.

If you are genuinely interested have a listen to this podcast by Jacob Bynum who is widely regarded as one of the most respected instructors in the world. He gives some amusing examples why coriolis doesn’t matter in shooting. 

https://itunes.apple.com/gb/podcast/gear-tasting-radio/id1203483156?mt=2&i=1000433535484

 

 

 

[Popsbengo]

3 minutes ago, TJC said:

Says most of the leading precision rifle instructors and top competitors. It’s actually common knowledge that most turn off this feature. Attend any high quality course and this topic comes up time and again.

If you are genuinely interested have a listen to this podcast by Jacob Bynum who is widely regarded as one of the most respected instructors in the world. He gives some amusing examples why coriolis doesn’t matter in shooting. 

Cheers, yes I'm genuinely interested - not being a dick.  Every day's a school day!

[That bald headed Geordie]

I think that if your a competitive shooter taking part in either F class or Benchrest at longer distance say up to 1000yds,  then you have enough time to shoot enough sighters as a precursor before the competition starts to 'get on'.     Therefore you can ignore Coriolis as you have enough to worry about mainly the wind picking up and dropping off as the competition progresses.

However,  if you are relying on hitting a target (live or cardboard) and need the 'one shot / one kill' then at longer ranges then Coriolis might have to be taken into account.   Especially if the target is small and not an elephant sized one.

But at Diggles longer range comps I have taken part in,   I do not believe that most shooters even give the Coriolis a moments thought.  

Just my twopennorth folks!

 

 

[TJC]

Jacob gives a very simple example of Felix Baumgartner, that guy who jumped from space. He took several hours to ascend to the edge of the atmosphere at 128k ft and then jump back to Earth in free fall for almost 5 minutes. Where did he land...pretty much exactly where he took off from. How is that possible if the earth is rotating around it’s axis at 1,000 MPH. The Coriolis Effect says he should have landed in the Pacific Ocean but he didn’t. In the two hours he took to go up the earth moved 2,000 miles (actually less because he wasn’t on the equator). Now think about a bullet. It doesn’t stay airborne for more than a few seconds and it doesn’t go that high either. The earth’s atmosphere moves with the rotation of the earth.

If coriolis mattered and I wanted to travel from London you Cardiff I would hire a helicopter and hover. The 150 miles would close in 10 minutes or so and all I would have to do is hover 25 feet above the ground.

If the earth moves at 1,000 mph how can an airplane travelling at 500 mph from say Madrid to Tel Aviv ever arrive ? It’s because the atmosphere is travelling at the same speed as the earth. If it wasn’t, we would have constant cyclones. 

[Popsbengo]

33 minutes ago, TJC said:

Jacob gives a very simple example of Felix Baumgartner, that guy who jumped from space. He took several hours to ascend to the edge of the atmosphere at 128k ft and then jump back to Earth in free fall for almost 5 minutes. Where did he land...pretty much exactly where he took off from. How is that possible if the earth is rotating around it’s axis at 1,000 MPH. The Coriolis Effect says he should have landed in the Pacific Ocean but he didn’t. In the two hours he took to go up the earth moved 2,000 miles (actually less because he wasn’t on the equator). Now think about a bullet. It doesn’t stay airborne for more than a few seconds and it doesn’t go that high either. The earth’s atmosphere moves with the rotation of the earth.

If coriolis mattered and I wanted to travel from London you Cardiff I would hire a helicopter and hover. The 150 miles would close in 10 minutes or so and all I would have to do is hover 25 feet above the ground.

If the earth moves at 1,000 mph how can an airplane travelling at 500 mph from say Madrid to Tel Aviv ever arrive ? It’s because the atmosphere is travelling at the same speed as the earth. If it wasn’t, we would have constant cyclones. 

I'm sorry but I've got to call you out on that.  A bunch of dumb examples and a total misunderstanding of the effect with respect to conservation of momentum.  A bit 'flat earth' if I may be so bold.

Coriolis is real, it's calculable and it's a measurable effect:  The fact that it probably doesn't matter at sub mile distances is not relevant to that.  I think I'd rather rely on science than anecdote. Brian Litz has useful things to say about the effect in his book.  As far as "ballistic calculators over calculating" I'm not buying that - it's basic physics and maths, why would the software writers deliberately over compensate?  Again, I agree the effect is small and down in the noise when other factors are in play but to say it's deliberately exaggerated is wrong - unless you know the app writers code is wrong?

[TJC]

If it is basic and maths why do different apps account for it differently ?

I love Brian’s work and follow him religiously but he’s saying we need a custom curve for bullet, he’s saying spin drift is more than many other ballisticians and he’s saying coriolis matters....and he’s selling software to measure and compensate for these. The truth is the best shooters in the word don’t use it and we all know in our sport everyone chases performance the the enth degree. If it made a difference at the enth degree shooters would embrace it religiously. You need to ask yourself why they don’t. 

PS I don’t they think are flat earth examples at all. They are simplistic for sure but they make sense don’t they ? The earths atmosphere moves with the earth. Outside of the atmosphere coriolis does exist, is extremely material but for the few seconds of bullet flight it doesn’t matter. 

Its super interesting but the reality is nobody has ever conclusively proved it matters for our sport. That in itself is interesting. There is argument and debate but if it is as simple, calculatable and basic physics as you say then why is there so much debate and discussion ? Is it because shooters have and haven’t seen the difference after firing billions or rounds downrange ?

[Chanonry]

6 minutes ago, TJC said:

1. If it is basic and maths why do different apps account for it differently ?

2. I love Brian’s work and follow him religiously but he’s saying we need a custom curve for bullet, he’s saying spin drift is more than many other ballisticians and he’s saying coriolis matters....and he’s selling software to measure and compensate for these.

3. The truth is the best shooters in the word don’t use it and we all know in our sport everyone chases performance the the enth degree. If it made a difference at the enth degree shooters would embrace it religiously. You need to ask yourself why they don’t. 

PS I don’t they think are flat earth examples at all. They are simplistic for sure but they make sense don’t they ? The earths atmosphere moves with the earth. Outside of the atmosphere coriolis does exist, is extremely material but for the few seconds of bullet flight it doesn’t matter. 

Its super interesting but the reality is nobody has ever conclusively proved it matters for our sport. That in itself is interesting. There is argument and debate but if it is as simple, calculatable and basic physics as you say then why is there so much debate and discussion ? Is it because shooters have and haven’t seen the difference after firing billions or rounds downrange ?

Ok so ...

1. It is a small effect. The errors inherent in the numerical models are likely to vary and on such a small effect may well produce different results depending on their exact initial configuration. How about that?

2. Confucius say "Man with two watches never knows the time". Who says he is wrong, maybe he has  a better model. Plenty other software has spin drift and coriolis options, as you point out. So why the cynicism?

3. They have other things to worry about for now that generate bigger errors? As the game progresses that may not always be the case. There are heaps of scientific advances that are don't have practical usage for decades. The AI algorithms were written tens of years ago but until we got big data, cheap compute, and the ability to load large databases across multiple processors they weren't much use. You can't just advance science when it suits you. Just wait until you can profile the wind with a laser.

As for the rest of it, you are being obtuse and I will leave you to it.

[TJC]

It’s a debate. Enjoy it. You could be 100% right or I could be. What we can probably agree on is that neither of us will ever be able to prove it on the range. I’m certainly not a good enough shooter for it to matter. 

[No i deer]

9 hours ago, brown dog said:

Attached Litz's piece on it.

The effects of coriolis vary according to both latitude and bearing of fire.

The effects are deterministic (ie you can quantify them with certainty) and make sense to include if your shooting discipline doesn't allow you sighters. But, with sighters allowed, coriolis is a layer of detail that, as others said earlier, is probably not worth bothering with.😊

ABDOC108_GyroscopicAndCoriolis.pdf

Deterministic....

Didn't know there was such a word,reading Alot of your replies BD I need a dictionary to translate them 😁.

Your the Steven Fry of UKV 😆😁

[One on top of two]

7 hours ago, TJC said:

It has no discernible impact in shooting sports.  

This ☝️

[Popsbengo]

46 minutes ago, No i deer said:

Deterministic....

Didn't know there was such a word,reading Alot of your replies BD I need a dictionary to translate them 😁.

Your the Steven Fry of UKV 😆😁

That's you're not your..😂

Can I claim the points please?

 

[No i deer]

25 minutes ago, Popsbengo said:

That's you're not your..😂

Can I claim the points please?

 

Somerset 😁

[VarmLR]

Coriolis might be something you account for within your shooting ballistic app where you're shooting long distance and are after a first shot on target...you'd include it because it is determinable  and not variable as such.  What is variable are some of the algorithms used to determine it (judging by the slight differences between various ones) and the bullet's velocity downrange.  I may be wrong, but as I understood it, the better ballistic apps allow for MV, and together with BC can determine a projectiles flight path and velocity at fixed points so some apps may well account for variations in velocity when calculating the Coriollis effect (I don't know for sure).

For target sports where you can get some sighters down-range,  it's doesn't really need considering as a few shots should see you on target, after which reading the wind has the biggest single effect (providing your loads are good and consistent).  I only include it because I use Strelock Pro has it and I've generally found that app to be spot on providing it's well enough calibrated.  I leave it on because at distance, with sighters allowed for, I've probably got more chance of mis-reading the wind effect as the app has of over-compensating for Coriolis so I don't lose sleep over it.  I have found Brian Litz to be an excellent reference and would trust his opinion over that of most on the subject unless he's proved wrong.

[Popsbengo]

3 hours ago, Gluv said:

I do believe there is an article on the hide about this. Apparently it is best to turn it off on your calculator because the equation is linear to account for the effect is linear whereas your velocity isn't .Long story short , you're making yourself less accurate!

Not my words, the words of Frank off the hide and some other rather serious shooters 🙂👍🇬🇧

I find that hard to believe Gluv.  Must have been written by some pesky foreigner chappy.

It's a major oversight if it is the case as it's reasonably easy to allow for the change in velocity.  As it's a trivial adjustment I'll apply it for the rosey glow of satisfaction knowing that I can claim the benefit when I hit the mile target 😁🇪🇺   Could be why you don't know where your bullets are landing 😂