Winds off?

[Kobyashi72]

Could someone help describe for me this “Winds aren’t matching the solver” issue that pops up in the podcasts now and then.

It seems to me to be counter-productive to be using a quick wind formula if it’s “off by half”.

Is it an intermittent problem? Are they separate issues?

I'm trying to understand the context and what should I be watching out for.

Thanks

 

[Deleted member 113831]

Could someone help describe for me this “Winds aren’t matching the solver” issue that pops up in the podcasts now and then.

It seems to me to be counter-productive to be using a quick wind formula if it’s “off by half”.

Is it an intermittent problem? Are they separate issues?

I'm trying to understand the context and what should I be watching out for.

Thanks

Truing the BC will change the amount of wind drift slightly. After all, wind drift for a given wind is determined by BC (all else being equal). At extended ranges, the difference adds up.

The quick wind formulas are a separate issue, but are tangentially related. If you don't know your true BC, your true "mil wind" to base your calls from will be off slightly.

 

[Mag1c-Mik3]

Im gunna try to explain more of this wednesday night.

 

[Timetoshoot]

What’s happening Wednesday night, are we invited, should I bring beer or whiskey?

The quick wind formula using BC has been an eye opener. It gives context and organization to decades of reading wind. It all of a sudden makes sense. Guess I’m a slow learner...

 

[Kobyashi72]

Is there full data for the Short Tikka LH gain twist project posted anywhere?
It would be helpful to have to follow along in Cold Bore with what's being referenced in the podcast.

 

[Lowlight]

No, I don't have project details beyond what is posted in the Tikka Videos I put on YouTube

The winds in most solvers are not right until those too are trued and by truing the BC we are talking about.

 

[Kobyashi72]

No, I don't have project details beyond what is posted in the Tikka Videos I put on YouTube

The winds in most solvers are not right until those too are trued and by truing the BC we are talking about.

Thank You Frank.

Out of curiosity were you seeing the “Wind Descrepency” for lack of a better term in the Spartan 260 Project lesson you made?

Do you have the wind values for that project?

Thanks again

I’m enjoying the podcasts.

 

[Lowlight]

You'd have to link me to what you are talking about, I have a lot of videos out there, and most of them I am not using Software based wind calls, I dope the wind myself and don't normally revert to the computer

But yes, the wind in solvers is normally off unless you true the BC.

It's the same as elevation, it has to be properly adjusted to line up right. The software looks at wind different than in the real world, in software wind moves in a straight and consistent line, which is not how real life operates. So, of course, there are issues with it.

 

[Kobyashi72]

My apologies.
Here's the link I'm talking about.
You focused on the elevation numbers but didn't really mention much as far as what the wind corrections were
I was curious to see how far it's off from the solver

 

[Lowlight]

didn't use the wind, I doped it

 

[Kobyashi72]

Does that mean you didn't record the numbers for the wind? I'm just seeking clarification as I don't have a military background.

"I doped it" is what has me confused as I thought one would record both elevation and wind for the data book.

Thanks

 

[Lowlight]

I did not record the wind, I just shot it based on my call I did not use a comptuer to give me a wind hold, I used my own brain so there was nothing to record, I just shot it and hit it

 

[Kobyashi72]

Gotcha. Thanks for taking the time.

 

[Emad]

Eddie here! I had Mike call me in mils. I use 3.5 moa per mil for quick math.
1=3.5moa
.5=1.75moa
.3=1moa
.2=.75moa
.1=.25moa
I got the wind to line up in my kestrel at what seemed to be a bit slow than the mil version 3mph @ .25 on my 308 with a +1 click at 600 I think. I'd switch to mil which is better for communication but I have several moa scopes so I'll do the math for now. I figure forward and backward with those numbers knowing it's a bit strong so drop a couple clicks if its several mils then believe the bullet.

 

[Deleted member 113831]

Eddie here! I had Mike call me in mils. I use 3.5 moa per mil for quick math.
1=3.5moa
.5=1.75moa
.3=1moa
.2=.75moa
.1=.25moa
I got the wind to line up in my kestrel at what seemed to be a bit slow than the mil version 3mph @ .25 on my 308 with a +1 click at 600 I think. I'd switch to mil which is better for communication but I have several moa scopes so I'll do the math for now. I figure forward and backward with those numbers knowing it's a bit strong so drop a couple clicks if its several mils then believe the bullet.

I'm curious as to why you would do the conversion rather than just calling in MOA?

 

[Deleted member 10043]

Practice in the wind so you can determine for yourself. Solvers are based on physics not that there is anything wrong with that except they can only solve for one direction and speed. Basically, there is no easier softer way than practical experience. Compare and contrast strikes with your golden dope and what the solver calculated to get an idea on what is really going on with the wind. Eventually, you will have a session with plenty if wind under the right conditions where the dope is zero.

 

[Emad]

I'm curious as to why you would do the conversion rather than just calling in MOA?

This post was intended to be in the 90 mil to moa thread so sorry to interrupt here. At the MH class the first day Mike was calling wind in mils for every one except me so to not break his rhythm I had him call me in mils and I would switch it. He was already calling for 308 6mm 338 300win mag so I felt he had a full plate! Most communicate in mil so if I'm on an moa scope I feel I need to be able to convert it.

 

[JMGlasgow]

If I true the BC to get the wind to line up, won't that also affect elevation?

I use Shooter, and while my elevation matches, wind is almost half what the software says I'll need.

 

[Kobyashi72]

If I true the BC to get the wind to line up, won't that also affect elevation?

I use Shooter, and while my elevation matches, wind is almost half what the software says I'll need.

Did you zero the gun in a crosswind? Are zeroing your group at 100 yards left of center to account for spin drift? Or are you centering your group on target? Did you record the azimuth/latitude to target? Rule those out first before you make adjustments to MV or BC

 

[JMGlasgow]

It's always windy here (WY), and please explain azimuth and latitude, and why they're necessary.

 

[Deleted member 10043]

If I true the BC to get the wind to line up, won't that also affect elevation?

I use Shooter, and while my elevation matches, wind is almost half what the software says I'll need.

Use the established BC. The solution for the wind is only off because of real world variables of the actual wind condition down range. Once you know your windage zero is correct and you see your windage app solution is off then back into the solution to get the correct average direction and speed for future reference.

 

[Kobyashi72]

It's always windy here (WY), and please explain azimuth and latitude, and why they're necessary.

Azimuth is the compass bearing to the target. It tells the solver where the Target is in relation to true north so that it can account for Coriolis on east/west bearing Latitude is what accounts for the horizontal component of coriolis.

The default state of the solver assumes that the zero conditions had no wind when it was zeroed. When you zero the rifle in a crosswind you’re zeroing in a component (let’s say it’s .1 mil) of your windage solution into your windage zero but the solver is presenting you a Solution based on NO WIND in the zero conditions

Your mechanical zero is not aligned with where the solver “thinks” the zero is

Later on when you hold-off for wind on a down range target it’s going to be .2 behind from what the solvers presenting to you cause it’s still thinks that there was no wind present in the “zero conditions” and you didn’t tell the solver that the zero moved

Edit: The reason you want to enter the latitude and azimuth is so the solver knows the correct “physics” that would need to be accounted for as part of your “Zero Conditions” before you make adjustments to the MV or BC

 

[Deleted member 10043]

Bullshit. Don't worry about compasses and how the world turns. You just need to know your app windage is limited to one direction and one speed inputs and that may not be the case down range. I think LL posted up a podcast on this topic on SH.com. It is important to understand the complex physics as sort of a prerequiset but we don't hand out certificates for it.

 

[Deleted member 113831]

It's always windy here (WY), and please explain azimuth and latitude, and why they're necessary.

The only things that cause your wind to be off as much as half are:

A. You are misjudging wind speed
B. You haven't entered the wind angle to your position correctly.
C. You have entered the wrong velocity (but if your drops are lining up this is not your issue)

 

[JMGlasgow]

Wind speed was measured by a calibrated wind meter that's installed on the shoot house, wind angle was as close as I could get it. If the wind is at 2:30, how do I enter that?

 

[Deleted member 113831]

@ JMGlasgow...OK, let's get the specifics and we'll see what's going on.
1. What program are you using?
2. What bullet and speed?
3. What altitude?
4. You've given 2:30 as the direction, what was the wind speed?
5. What is your app saying your drift should be?

 

[JMGlasgow]

Shooter
Hornady 140 eld-m
Chronographed at 2740 w/magnetospeed
Actual altitude of 6062
Wind speeds were variable but averaged 16mph after watching the meter for a minute or so.

Spin drift, and Coriolis were turned off.

 

[Deleted member 113831]

Shooter
Hornady 140 eld-m
Chronographed at 2740 w/magnetospeed
Actual altitude of 6062
Wind speeds were variable but averaged 16mph after watching the meter for a minute or so.

Spin drift, and Coriolis were turned off.

OK, drift should look something like this:

100 - .6 moa - .2 mils
200 - 1.3 moa - .4 mils
500 - 3.5 moa - 1 mils
800 - 6 moa - 1.7 mils
1000 - 7.8 moa - 2.3 mils

I ran this on both Strelok Pro and Hornady 4DOF. What were your results?

 

[Kobyashi72]

Bullshit. Don't worry about compasses and how the world turns. You just need to know your app windage is limited to one direction and one speed inputs and that may not be the case down range. I think LL posted up a podcast on this topic on SH.com. It is important to understand the complex physics as sort of a prerequiset but we don't hand out certificates for it.

He asked about truing the BC

example:
Actual target facing 270 W

(Settings turned on) 1000 yd 7.4 mils@ az:270 W rem v=1669 tof = 1.370 BC= G1 .563

(Settings turned off to match shooters’ 12:00 Orientation to same target) 1000 yd 7.4 mils@ az:0 N rem v=1636 tof = 1.384 BC= G1 .545

 

[JMGlasgow]

I went out to the range again this morning. Winds were fairly calm, increased as the day went on. No actual wind reading because the meter apparently can't read winds under 10mph. It also now makes me question how accurate it really is. Here were the environmentals I could get:

Temperature: 60℉
Wind: guessing around 6mph (I was pretty close apparently)
Altitude: 6062
Same bullet, same speed
I set humidity at 50% because I was told it doesn't really matter.

Wind holds were very close to what the software said it should be. I'm really not sure what happened besides the wind meter at the range is not accurate. Landscape plays a roll downrange because there are rolling hills and valleys.
I also shot my 30-06 hunting rifle, and my 308 Savage with a new Varmint barrel. Both of those were very close in wind calls as well.

I just need to break down and get a Kestrel.
I also input the different BC's that Hornady has for the different speeds
6.5mm 140 gr. ELD Match
Mach 2.25 2512fps
0.646 G1
0.326 G7
Mach 2.0 2232fps
0.637 G1
0.320 G7
Mach 1.75 1953fps
0.616 G1
0.310 G7

 

[Deleted member 113831]

I went out to the range again this morning. Winds were fairly calm, increased as the day went on. No actual wind reading because the meter apparently can't read winds under 10mph. It also now makes me question how accurate it really is. Here were the environmentals I could get:

Temperature: 60℉
Wind: guessing around 6mph (I was pretty close apparently)
Altitude: 6062
Same bullet, same speed
I set humidity at 50% because I was told it doesn't really matter.

Wind holds were very close to what the software said it should be. I'm really not sure what happened besides the wind meter at the range is not accurate. Landscape plays a roll downrange because there are rolling hills and valleys.
I also shot my 30-06 hunting rifle, and my 308 Savage with a new Varmint barrel. Both of those were very close in wind calls as well.

I just need to break down and get a Kestrel.
I also input the different BC's that Hornady has for the different speeds
6.5mm 140 gr. ELD Match
Mach 2.25 2512fps
0.646 G1
0.326 G7
Mach 2.0 2232fps
0.637 G1
0.320 G7
Mach 1.75 1953fps
0.616 G1
0.310 G7

Where are you finding the banded BC's for the Hornady bullets? I've looked all over the website and the 4DOF calculator on my phone and can't find them.

 

[Kobyashi72]

Where are you finding the banded BC's for the Hornady bullets? I've looked all over the website and the 4DOF calculator on my phone and can't find them.

https://www.hornady.com/support/ballistic-coefficient

 

[JMGlasgow]

The link above was where I found it.

 

[Deleted member 113831]

https://www.hornady.com/support/ballistic-coefficient

The link above was where I found it.

Thanks guys, I found it. Interestingly enough, if I typed in "ballistic coefficient" to the search box, it comes up. The Ballistic Coefficient tab says it should be under "support", but proceeding from the home page forward, there is no path from "support" to "ballistic coefficient". It is essentially hidden unless you know to type it in. Strange.

 

[Kobyashi72]

It was under Hornady.com >> Bullets >> "ELD Match"
just below the "fold" red button labeled "See All ELD Match and ELD-X BC Values"
It's not very obvious and could easily be missed