ELR Thoughts from this Past Weekend

[Lowlight]

This past weekend I had a friend from Alaska come to Colorado to shoot ELR At my Range.

We have targets every 100 yards to 1775, and this weekend we added a second target to 1815 yards, why not.

James came down with only 110 rounds of ammunition, 60 for his 300NM, and 50 for a 37XC, the focus is quality, not quantity. We wanted to look at confirming the software, gaining confidence in the systems, working in the wind, and being able to successfully engage targets on command.

So we have goals in mind and I am working on a process for guys who want to engage in ELR Shooting and being able to reference the data in a meaningful way. We are looking for patterns here, as an example, we learned if we round his software down to the nearest tenth the impacts were much better. They did trend low, but lower was easier to spot, to adjust with, and keeps everything on the target or at least very close in the FOV. We found even low we still impacted the plate very well, and with most of the shots, the targets were very close to the waterline.

I have an idea for a plotting system or databook layout as we do things slightly differently than in the past. The idea focuses on less of a book or more a folder that holds your electronics and well as giving you something for notes. It's more of a battle board design vs a traditional databook as I don't think we work the same as we once did.

We had great conditions, the first day was a very light wind, 2 to 3 mph. Perfect for collecting data. The second day the winds grew from 3 to 8 and then ending up on the final shots around 12MPH before jumping to 20+ on the way home.

Hits were all solid:

Actual vs Predicted

One of the keys to shooting ELR is determining the software's ability to stay on track. We find the software is fickle at these ranges but so is the ability to correctly range the target. I used my Vectronix as well as knowing the layout of the range. Ranging was a big key, so much so I realized for every shot we needed a checklist not just for the range, but also for the conditions. We found a single lapse in updating the atmosphere at beyond 2000 yards resulted in a .1 variation. This was just an 800ft DA change, but it was enough to be visible. That point can put you over the top or just in front of a target.

Through our recording keeping, we found the pattern, round low, then manage the wind. WTF added an additional "F" to the equation. Normally WTF is Wind, Target, Fundamentals, but in this case, it was Wind, Target (range) Field Conditions .. weather



I am happy to say we hit a lot more first-round impacts than we missed and every target was pretty much an odd range, we just moved to a spot that gave us a decent FOV on the targets, dropped down, ranged it, and engaged them. This is helpful with the software because we had to be right and we see where the variation lies at these distances.

The plates as big as they are can only suffer .2 mils of variation elevation wise. The math might say otherwise, but the reality was, in the cases, we purposed adjusted off and then back on we found .2 was the limit, any dancing of the turrets past that probably means a miss.



SD & CE,

it's wrong, just stop, I get it, but it's wrong.

I did not use it once but we calculated the effects after the fact, so We had SD & CE turned off, but that does not mean we did not check it every shot to see what the computers fed us. Wrong, enough said, it's wrong.

Windwise I had Wind Finder Pro and a local Airport less than 4 miles away. So I had solid prevailing wind data. Wind Finder Pro gave me 3 MPH. I read an average of 2 MPH at my location and used that on the first day. Our hits were solid with more first-round hits than misses.

It's the wind, that's it, I actually shot a video on this in real-time but I hesitate to post it because people with next to no experience doing this will argue the other direction. My hit rate is unmistakable, so while I understand what the math says, it's wrong.

My calls are solid,

As I said, I did a video of this during the shots, so it's not revisionist history, it's in the moment.

I really am tired of arguing the fact, but let's be honest, without these built-in excuses what are guys gonna blame when they miss. We turned it off and never mentioned it during the shot, only after to see where the computer would have put the shot vs my call.

Dope the wind, seriously, we are truing against data with it included we dont' need it twice.

The last comment on the subject, check your numbers, run them with and without and look at the wind, what is it doing We had wind from the left, so that would be more right-leaning drifts, but even still it's the wind call, not the drifts.

">

 

[ZiaHunter]

What software?

 

[_Windrider_]

The notebook is something I already use. I also use a traditional impact data book in conjunction. Been trying to figure out how to consolidate this into a small package. I also use a battleboard FIST. Would be an awesome collaboration if we can come up with a “sniper” package for mil and civ shooters. I really like the battleboard system.

 

[Lowlight]

He used Trasol

I have a great idea for the battle board !
I also have mocked up a worksheet

 

[Lowlight]

Just a note on the software side,

Trasol tends to be pretty good with CE and SD, it's around 1.5% vs the typical 2% you see with other software.

The other issue with software is the truing, many true the software to their real-world results, then turning on SD and CE you are doubling the value on top of the actual value, so this is why I say it does not work. You are stacking errors on top of each other.

if I shoot a target that requires 10 mils to hit it, then I go to my software and tell it, I used 10 mils to hit this target that is a validation of fact. However, if I tell the software I used 10 mils to hit a target and I want to hit it again, and I turn on SD & CE I have changed how the computer sees this target and this will result in a miss, you changed the values.

This is my contention and my results seem to validate these observations, predicting in a vacuum is one thing, predicting based off real-world results is different,

 

[timintx]

Just a note on the software side,

Trasol tends to be pretty good with CE and SD, it's around 1.5% vs the typical 2% you see with other software.

The other issue with software is the truing, many true the software to their real-world results, then turning on SD and CE you are doubling the value on top of the actual value, so this is why I say it does not work. You are stacking errors on top of each other.

if I shoot a target that requires 10 mils to hit it, then I go to my software and tell it, I used 10 mils to hit this target that is a validation of fact. However, if I tell the software I used 10 mils to hit a target and I want to hit it again, and I turn on SD & CE I have changed how the computer sees this target and this will result in a miss, you changed the values.

This is my contention and my results seem to validate these observations, predicting in a vacuum is one thing, predicting based off real-world results is different,

Frank , Is there a way to adjust values to percentages of the original calculated value of CE and SD with any software available?

 

[ZiaHunter]

Attended the Gunsite XLR class (3rd time) this past September with the object of dialing in my 375 SnipeTac and brought a 338LM along as well. Wound up being the only when in the class when the other including the HMFIC couldn't make it for whatever reason and this was the second time I was one on one with Cory. In previous classes calibration was done by sending rounds down range at KD targets then adjusting FFS to match the actual dope. This class we used the Labrador and Shot Marker system to calibrate. It was accurate and minimized the amount of rounds fired which is a benefit for the 375 due to the short barrel life 400gr Flatlines were being fired out of the 375 and final calibration required tweaking DK while the 338LM firing 285gr ELD's only MV and BC were adjusted. First round hits out past 1800 pretty consistently with Cory's wind calls. Luckily since I was the only one in the class we were done before noon every day since the wind and mirage stated coming up late morning.

 

[Geno C.]

I run TRASOL as well. It’s been very solid for my out to at least 3000. I don’t he CE on but I do have SD. I trued my data with it already on though instead of trueing with it off and the turning it on

 

[Lowlight]

SD and CE are flat-rate values based on TOF (usually)

They normally did 1" (10) at 1000 yards with 1 sec TOF, or variations of that...

They are not being calculated in our apps. It's roughly 1% of elevation if you stick to that you find the apps are doubling it, if not tripling it, but using 1% is a better representation of the facts we observe

 

[Lowlight]

The Gunsite trip was for AI, it was thankfully canceled, enough on that subject.

 

[Geno C.]

It reduces 2.7moa for me at 3000. Sure wish I could find a calm or even semi calm day to shoot ELR distances and see how they compare to my calls.

 

[Lowlight]

Do this, look at your software, put in these conditions

2400 yards

2 MPH Wind at 8:30, also look at how much 1 MPH pushes it

It should be about .4 of SD, maybe a tick less, if you do 1.25% of elevation that should include it all

 

[Geno C.]

SD accounts for 1.1 moa and 1mph accounts for the same. I consider myself pretty decent at wind calling but I couldn’t tell if my 12mph was actually a 13 or not over that distance.

that’s with a 1-10 barrel. My 338 with a 1-8 shows SD at that distance is 1.25 and 1mph of wind is .75

 

[pmclaine]

Excellent.

Questioned why SD/CE would be turned off - what could it hurt - but makes sense its already accounted for in your zero.

Ill turn it off.

Sig Sauer incorporates both in their PSR classes.....next one Ill be sure to say "Excuse me Frank Galli says......"

How about "aerodynamic jump"? Sig pushes that also? It makes sense scientifically I guess if its a constant its another factor contained in your zero or DOPE.

Its good info to know but sometimes science/theory does not apply in the practical world.

Im kind of simple and I dont get the luxury of the beautiful ranges you Big Sky "Comrades" (we are all Comrades now) get to shoot.

My SD/CE/ADJ are all contained in "Center", "Edge", "X mils L/R off".

 

[HousePlant]

Patiently waiting for an invite to your range.

 

[Lowlight]

Sig Academy, Enough Said, LOL

when you talk about all the fringe stuff, and harp on these microscopic drifts for an hour, it's easier to miss the fact they aren't really teaching you anything, they are repeating a bunch of stuff with no practical application behind it, (because they can't demonstrate it, nor will you ever see it ) so you think they are giving a bunch of insights when really they are camouflaging the fact they can't teach the important stuff so let's focus on the minutia

Dope the wind, confirm the limits of your elevation, the rest will fall into place.

We never mention it, I just don't bring it up, and our students have a nice hit rate, ask someone who's been to class. We talk fundamentals, we talk Wind, we get hits.

 

[CoryT]

I'm going to disagree. While SD and CE are pretty much a non-issue at ranges inside 1000 yards, I suggest applying corrections past that range. I can't speak for all solvers, but if the value is being calculated, not just estimated, the value is correct. Now, how one makes use of the value becomes the issue.

If you are fairly new to the ELR game and are jumping right into 1500-2000 yard shots from a 600-800 nominal range experience level, not correcting the additional lateral drift will make accurate wind calls difficult to learn. This is the example from my class. For a specific 250gr .338LM load at 2970 under normal conditions here at Gunsite, SD = 33.4" and CE drift is 8.4" for a total of 41.8", or .6 mils. If you were working on a zero target at 100 yards and were .6 right to group center, would you not dial on .6 left to get the group to center? If you don't, you have placed a bias into your wind call, if you see the wind as a particular value, say 10 MPH, you will need to call a different hold depending on the wind direction. That's going to make learning difficult. Under these conditions, 1 MPH of wind is 16.7" of drift, less than half the SD + CE.

If you don't put in the correction is that why you miss? Well, not in and of itself. If you've been shooting long range for a very long time and worked up into the ELR game over some time, what's happened is the drift has been baked into your wind calls if you did not start with SD + CD dialed on. If you hit, the correction is in there, you just held it instead of dialing it. That's fine, you can certainly do that, but I would not suggest that as a way to learn to do it. It's easier to dial on that correction, 'zeroing' the windage at the range, now any drift you have is wind (presuming the shooter is competent). Now the downrange effects you see apply equally in either direction, so it will be easier to get a good call the next time you see those effects, not matter the direction.

The human brain is a pretty marvelous system of seeing patterns, retrieving data and making decisions. Leave SD + CE off. Now what happens is you simply see L to R and R to L as different values for the same physical effect. You make a call, you hit. You link that to what you saw. You miss, correct, then hit. Another link. Enough shots down range and you have a perfectly usable system. That does not, however, make the SD and CE values 'wrong'. They simply do not apply to your method, and that's fine, more than one way to get a solution for sure.

Try an experiment. This takes a while, but it's informative. Over the course of a year, chart your misses left and right for shots you called the wind on. You need enough data, you must shoot in varied directions and in varied directions, at equal width targets, etc. If your distribution of L vs R misses is about equal, your system works. If it trends R by a significant amount, perhaps you should dial on the corrections if you have not. If it trends L and you dial on, perhaps you should not.

As to truing, it certainly matters if you computed the estimate with the solution refinements on or off. If the computer is using SD+ CE + AJ etc, and you try to true your elevation against a solution where you turn that off, that will be the same as a mismatch in conditions or range, garbage in gets garbage out. If you are going to true the computer, you need to turn on the features you intend use in the field and enter the actual field conditions for the shots. You can't true with SD and CE off, then compare that solution to SD + CE on. If you have vertical deflection on for example, and use the elevation value in a 10 MPH L to R wind, then the computer better have that 10 MPH wind entered when you compare your 'real' dope to the computer 'projected' value. Once you are 'trued', you now have to leave that turned on and you need to enter the wind value when you compute a solution, or you are going to be inserting errors into the solution. If you don't enter wind values, then don't turn on AJ or VD and make sure you true with them off. You can't just setup the computer for one set of conditions and elect to turn on some features like SD and not have some issues.

 

[Lowlight]

It's wrong

Period and I can prove it from a Gunsite class,

We had multi 300NM mags at the class, I was on glass because my gun went down, I had 3 guys on target, zero drama at 2000m. We all used 6MPH for the wind call and we had everyone on point. Up steps, Jeremy C and he shoots with his Norma is on the wrong side of the plate and the wind. The next call to hit based on his first shot was backward, pretty easy to see, the wind is coming LEFT and he has to hold RIGHT to hit it.

I asked him what was on the gun, based on AB Kestrel the program told him at this distance, 2000m+ he needed .8 of SD for his shot. So he dialed it, as you all instructed, to use it. I told him to take it all off and Tessa snapped back to put it on then went through these same regurgitations of these bullshit numbers. (Cause when you adding fake numbers it sounds better)

So in front of Tessa we ran all the numbers we looked at each shooter and their data, it's .3 Mils of SD vs the wind call, even blowing the wind by 2 MPH it's .3 not .6 or .8 it's pretty clear to see. I know this is right because I often attempt to TRUE The wind to get better numbers, this was as solid as you can get. Guys shooting the same caliber, guys shooting the same conditions, and one guy on glass making the calls. When 1 out of 5 doesn't fit the mold, we looked and found out why. Cause he dialed it on as instructed at Gunsite.

I don't about all this, but if you need to hold the reticle on the down wind side to hit the target something is not right. In this case it was .8 for SD which sounds pretty close to your .6 which is still wrong, that is twice as much as I suggested with my understanding of the facts.

We had PERFECT conditions, we had wind read at both the target and shooter and I have very little by way of terrain in to mix up the wind.

There is not a lot to mix the wind-up, and Windfinder Pro showed 3 MPH at the airport which is just down the road, and I was running my kestrel too... which read 2 MPH

So there is absolutely NO WAY the wind will line up when you add in the SD according to the software. it's overdoing it by 100%. If the real answer is closer to 1% and the computers run around 2 to 3% in the solution you are doubling and tripling it. Not saying it's not there but it's WRONG.

The numbers have to be adjusted for the fact the Earth drags its atmosphere with it, Corilios is MACRO not MICRO which is why we can breathe, there is no offset for the formulas to account for the air moving with the Earth, and this matters. Ask Felix Baumgardner why he didn't land in the Pacific Ocean, the math for his jump said 75+ miles from his starting point, he landed 23 miles away. Run the numbers, just like you did above.



Also on SD, wind matters, sometimes it helps, some times it hurts it, for me I would rather work the wind than play with minutia

 

[Lowlight]

And PS

The fact we can true a computer with this stuff ON or OFF which is exactly what happens, and the data still works should tell you something right there.

We know, if you shoot in the real world, and match the computer to it, regardless of which method, people get statistically even amounts of hits. There is no data that shows one way excels vs the other. Yes on Paper we can argue the math says, X, but we all know in the field Y Is all too common.

I think we can absolutely do it both ways and it will work. On top of that, the plates average 2 MOA and we dealing with something that is less than 1 MOA, so it's easy to add and say it works or not and claim the same thing. Because it's small.

That is point, it's small, it clearly works in both directions so not sure how it gets resolved?

 

[Lowlight]

I think as an experiment here, have everyone pick a different program and turn it on,

Give the different calibers and devices the same data, as far as elevation goes, and then give it a standard wind and see what it says, do it both ways, the wind from the left, then from the right

Do something like 24 Mils of elevation and see what the numbers say with both CE turned on and then off, left then right wind, and if the programs are all different, which I suspect them to be, how are they calculating the value is my question ? Or use MV give all the calibers the same ending MV like 1200fps at the target

We already know the software doesn't "agree" with each other, Hornady 4 DOF values are different from AB which are slightly different from Strelok which is definitely different compared to TRASOL

So lets the numbers laid out

 

[Lowlight]

I have math too

Why won't Felix travel the same value the math predicts...

The Effect of Wind on the Stratos Space Jump

How much will wind affect the Red Bull Stratos Jump? Dot Physics blogger Rhett Allain dissects the physics of Felix Baumgartner's upcoming stunt.

www.wired.com

How about a comparison? What if the jumper started at rest with respect to the rotating Earth? How much would the displacement be in that case? I don't even really need to model this one. Let me just take the falling time of about 300 seconds. How far horizontally would the Earth's ground move in this time? Of course this depends on the location of the jump. The official launch site is in Roswell, New Mexico. This is located 33.39° above the equator. Here is a diagram of its position on the Earth.

The rotational speed of the Earth is about* once a day, this is 7.27 x 10-5 radians per day. (* don't forget the difference between sidereal and solar days - but the difference hardly matters here). To find the velocity of a point on the ground, I need to radius of the circle that point is moving in. From the diagram above, this will be:

Using the radius of the Earth (6.38 x 106 m) and the latitude of Roswell, this gives an distance of 5.33 x 106 meters. The velocity of the ground will then be:

Putting in values from above, I get a speed of 387 m/s. So, in 300 seconds the ground will move 116 km (72 miles). Crazy, right? but remember in a whole day, this point on the ground has to go ALL THE WAY around the Earth. At this latitude, this is a path length of 20,000 miles.


So, why won't the jumper (Felix) be displaced by 70 miles when he jumps? Simple. He starts his jump with a velocity of about zero m/s relative to the ground. Yes, since he is higher up, he will have a different linear velocity than the ground - but the difference is super small.

After all these years I have not changed my mind on the subject that has to tell you something, cause as the scientist says, its super small

He models the wind drift too and wonders why he barely moves he includes air resistance to his models

I have previously modeled the motion of a skydiver from that extreme height. How do you do this? If you consider a jumper falling straight down in a no-wind situation, you would have this force diagram.

So, we are dealing with two forces during this fall. First, the gravitational force. Even at 120,000 feet, it isn't a terrible approximation to say that the gravitational force is:

Where g is the gravitational field with a magnitude of 9.8 N/kg and pointing towards the ground (it is just about 1% less than the universal model for gravity - you know, the 1/r2version). So, I will just say this gravitational force is constant.
The air resistance force is a little bit more complicated. Here, I will use this model.

Although you may have seen this before, let me point out all the details.

• ρ is the density of the air. This will clearly change with altitude.
• A is the cross sectional area and C is the drag coefficient that depends on the shape of the jumper. I will estimate both of these values based on the terminal speed of a normal skydiver. Also, C could probably change with super high speeds, but I will ignore that aspect.
• v - this is the velocity of the jumper. But really, this is the velocity of the jumper with respect to the air. If the air is moving, we call this wind.
• If you are wondering about that last v with the pointy hat on it, we call that "v-hat", get it? It is just a unitless vector in the direction of the velocity. This will make the air force also a vector.

Now what about this "velocity with respect to the air?" Let me draw another diagram for the case of a falling person with a horizontal wind.

I know this looks confusing, so let me explain. There are three velocities that are important.

• The velocity of the jumper with respect to the ground (labeled jg). This is needed to find out how far horizontally (and vertically) the jumper moves.
• The velocity of the air with respect to the ground (labeled ag) - yes, the wind.
• The velocity of the jumper with respect to the air (labeled ja). This is the velocity that goes into the air resistance force.

When dealing with relative velocities, I can say these three vector velocities satisfy the following:

Ok. I think I am ready for a numerical model. One more reminder of the numerical model methods. First, break the problem into a whole bunch of small time steps. During each short time interval:

• Calculate the forces on the jumper. This will include determining the altitude to get the density of air and the velocity of the jumper with respect to the air - both of which are important for the air resistance force.
• Use the force from above to determine the change in momentum of the jumper and thus the momentum at the end of this time interval.
• Use the momentum from above to find the velocity and the new position of the jumper.
• Update the time and repeat.

Simple. So simple even a computer can do it.



Anyway Wired won't give me more without subscribing

 

[Deleted member 113831]

The numbers have to be adjusted for the fact the Earth drags its atmosphere with it, Corilios is MACRO not MICRO ...

 

[oneshot.onehit]

All I can say is I run the Cold Bore from Patagonia using SD, CE with great results at very extreme distances. To consider not using would only help my competitors, I don’t think I could consider the fact.

Question, why would anyone go through the process of trying to true up their programs to match impacts at distances with the SD and CE shut off then after the fact turn them on thinking everything is good to go - anyone that takes that route does not understand Ballistics programs.

I can’t complain about the results I’ve seen from fellow shooters using Trasol and Field Firing Solutions as well They all preform very well and utilize SD and CE as well while monitoring the wind conditions and not really fudging the numbers.

We all know wind is a challenge we just use our best judgment and science to focus on hitting small targets at the extreme distances under a time restraint.


Theories and science with debates testing pushes the limits in which excels in time.
Cheers

Oneshot.onehit

 

[Lowlight]

I am confused, who is saying turn the SD CE off and then On...

I just leave them Off, I don't toggle between them being on or off,

and Why true something to something to a value already included. If I need 10 Mils to hit a target, it's not 10 Mils +SD +CE +AJ, it's just 10 Mils ... so why do I need to turn something on that is already on and included ?

But I just leave it off, I never use it, if someone is reading this differently, nope, that is it. I always use it off.

 

[pmclaine]

Sig Academy, Enough Said, LOL

when you talk about all the fringe stuff, and harp on these microscopic drifts for an hour, it's easier to miss the fact they aren't really teaching you anything, they are repeating a bunch of stuff with no practical application behind it, (because they can't demonstrate it, nor will you ever see it ) so you think they are giving a bunch of insights when really they are camouflaging the fact they can't teach the important stuff so let's focus on the minutia

Dope the wind, confirm the limits of your elevation, the rest will fall into place.

We never mention it, I just don't bring it up, and our students have a nice hit rate, ask someone who's been to class. We talk fundamentals, we talk Wind, we get hits.

They are the best alternative in a region of limited options.

Odd but shooters from the northeast, once they move out west, never want to return to help out their homies in commie land .

Sig doesnt stress it. Its like they read an Applied Ballistics book and "the science" attracts them because they know there will be students in the room that are getting stiff thinking how technically adept they will be once they get the certificate. I can picture them at their home range bragging about their training than tell those watching their misses were the result of not adding CE to their solution, oh and the next one was becuase the forgot SD, damn missed again because of ADJ!

Once you get out on the range its more a case of them ensuring you got a tight zero, checking your fundamentals, than letting you send it at your own pace.

If you are halfway competent you kind of get left alone. They will answer and help you with anything you want to work on but usually there are others in class they need to spend more time with.

I do find at times I would like someone to perhaps critique position, trigger manipulation and follow through more closely but Im not going to pipe up in class and be that guy.

Its a sausage factory for sure. Currently signing up for classes is a 6-8 month in advance endeavor. Its like signing up for that college class you need to get credits on toward your degree and you keep checking the catalog to see if available because you dont want to miss it and get fucked.

If you ever decide to come to the northeast for a class Ill kick my son out of his room and let you stay. Its a twin bed, you will fit.....

Semper Fi!, Happy Birthday.

 

[CoryT]

Since I can easily track 4-5 miles from the exit point on a 30K foot HALO jump, I'm not sure the parachutist model explains much. I have the luxury of living right on the range, I can literally step out my bedroom window, lay on the roof and shoot at 1200m. I dial on the SD+CE value and never have a problem with wind calls, and the targets at 1200 to 1500m are all 18" wide. One of the first YT vids I ever posted about XLR here at Gunsite shows 3 consecutive hits, starting from cold bore where we hit the 10" center plate on the Vlei flipper and we had the correction dialed on.

Could various programs have it wrong? Sure. I advise FFS and Coldbore and I can't complain about the values I get from them.

Without a fully instrumented test range, the rifle in a fixture, Doppler bullet tracking and LIDAR wind cubes, you can't say for certain why a shot landed where it did.

At 2000m, a good CEP is probably 16" to 20" in diameter. You center punch a 24" wide plate and think 'Man, got the wind call perfect!'. The shooter held .08 less than you called, broke the shot a bit less than clean making it .1 and it was the leftmost shot of the 20 round group you'd need to prove out the actual CEP, so that shot is really about 17" left of where you actually called, so instead of a miss you got center.

Basic rule, don't argue with success. You are happy and successful leaving it off, drive on. I'm equally happy with it on.

 

[CoryT]

I am confused, who is saying turn the SD CE off and then On...

I just leave them Off, I don't toggle between them being on or off,

and Why true something to something to a value already included. If I need 10 Mils to hit a target, it's not 10 Mils +SD +CE +AJ, it's just 10 Mils ... so why do I need to turn something on that is already on and included ?

But I just leave it off, I never use it, if someone is reading this differently, nope, that is it. I always use it off.

And that's fine, it is included and you have trued to that value. If however, you turn it on it would result in a different elevation, so as you state, pick one way and stay with it. Note however that you are increasing your elevation error range. Since the CE elevation correction changes with the direction and latitude, when you change that the correction is not being made, so your uncorrected solution is off by some small amount. Since it's mostly about .1 mil or so, it's probably nearly impossible to tell given all the other approximations made during a shot, kind of like dialing for SD on a 500 yard shot.

 

[oneshot.onehit]

Frank
Just referring to comment #5 where you stated some folks, not so much yourself.

Each to his own run what works for your solutions that seems successful and pull some trigger.

Cheers
Oneshot.onehit

 

[MCHOG]

The numbers have to be adjusted for the fact the Earth drags its atmosphere with it, Corilios is MACRO not MICRO which is why we can breathe, there is no offset for the formulas to account for the air moving with the Earth, and this matters. Ask Felix Baumgardner why he didn't land in the Pacific Ocean, the math for his jump said 75+ miles from his starting point, he landed 23 miles away.

That is the best explanation I have heard as to the cause of the discrepancy. Truly insightful.

 

[pmclaine]

That is the best explanation I have heard as to the cause of the discrepancy. Truly insightful.

Just thinking to myself.........probably dumb/redundant.

Constant state of hurricane if the opposite were true.

Except we would be at the velocity of earth and the air would be stationary.

Air acts like a liquid.

Put a spinning ball in the middle of a pool of water, given time the whole pool of water will be moving at a similar rate in unison with the ball.

Relative to each other there is no movement between ball and water.

So why would you correct for anything outside of temporary forces (weather) because everything being equal everything in the pool is a constant and accounted for in your natural state (zero).

Why you should zero on a "windless" day.

 

[CoryT]

That is the best explanation I have heard as to the cause of the discrepancy. Truly insightful.

Except it's not accurate. The better example of the problem is tossing a ball on a merry-go-round. From the point of view of the riders, the ball appears to curve in it's path. An outside observer sees the path of the ball as straight. This is not due to air resistance.

Once the bullet leaves the barrel, it behaves just as the ball does. The atmosphere does NOT 'drag' it along. It has a radial velocity of course, which starts to decay, but that radial velocity is very tiny anyway. It's half the radial velocity of the hour hand on your watch. The ball in the bucket of water is an example of friction in a closed system. Look at the direction and velocity of the jet streams.

If the effect was only macro, then Foucault's pendulum would not work.

 

[LastShot300]

Except it's not accurate. The better example of the problem is tossing a ball on a merry-go-round. From the point of view of the riders, the ball appears to curve in it's path. An outside observer sees the path of the ball as straight. This is not due to air resistance.

Once the bullet leaves the barrel, it behaves just as the ball does. The atmosphere does NOT 'drag' it along. It has a radial velocity of course, which starts to decay, but that radial velocity is very tiny anyway. It's half the radial velocity of the hour hand on your watch. The ball in the bucket of water is an example of friction in a closed system. Look at the direction and velocity of the jet streams.

If the effect was only macro, then Foucault's pendulum would not work.

Curious about the difference between macro and micro? What would be the difference when going ELR?

 

[CoryT]

That's the point, there is no difference (at least above the quantum level). The only issue is if the effect, as small as it is, is overridden by other outside forces. Take a shot at 600 yards with a .308, the SD and CE effects are very small, on the order of .1 - .2 mil, or 2", about the same as 1 mph of wind. Since you can't read wind to 1 mph, the effects are masked to the typical shooter. The effect exists, but it's 'lost in the noise' of all the other uncertainties.

In my example above, the effect is now more than double the width of the target. Unless you adjust for it in some fashion, you simply cannot hit the target. It's exactly the same as a 100 yard shot on a 1" dot where you are 2" left of center. You can either dial the correction or hold it, but if you want to hit the dot you must do something.

If you hit a target in the center at 1800m, you applied the correction, either explicitly (dial on) or by having it integrated into the wind call. Without extensive instrumentation it's not possible to say with precision what conditions were over the bullet path and exactly where the gun was pointed at the moment the bullet released. You can't just work the problem backwards and say, these two wind meters say 3 mph, and that's what the wind call was, so the effect was not there, or it was half the prediction, or much of anything else really. The number of thing I DON'T know about that shot far outnumber the number of things I do know.

 

[LastShot300]

You can't just work the problem backwards and say, these two wind meters say 3 mph, and that's what the wind call was, so the effect was not there, or it was half the prediction, or much of anything else really. The number of thing I DON'T know about that shot far outnumber the number of things I do know.

Great piece of actionable knowledge. thanks!

 

[LastShot300]

All I can say is I run the Cold Bore from Patagonia using SD, CE with great results at very extreme distances. To consider not using would only help my competitors, I don’t think I could consider the fact.

Oneshot.onehit

That is the reason I'm eagerly waiting for Genesis to hit the shelves, at least for Android.