Trueing software and wind

[Timetoshoot]

After listening to the Pocasts about wind and the Kestrel I had the opportunity to work with the info from both pocasts. ...This past week I began work with a new sig 2400. I used the custom drag curve and a good speed from 4 five shot chrono sessions over the course of two weeks . I set wind to zero mph and zero degrees. Dope was spot on from 550 out to 1200 yards. I wanted to true my kestrel 4500 to match the dope from the 2400. I did not change muzle velocity, I changed the BC from .43 to .46. My kestrel and Sig match each other and real world dope from 550 to 1200. It will be interesting to shoot in changing conditions and locations to see if they continue to track with each other and actual dope.

I used the BC wind method as a base, it worked out well, looking at dope sheets from the past year using the BC method would have put me within .1 for most actual wind calls

Elevation was 5600ft, barometer 24.8, 6.5 CM 107smk at 3097fps. Printed G1bc is .430, trued is .460

Great information, thanks for sharing.

 

[Mag1c-Mik3]

We did a shoot this last weekend with 5 shooters no kestrels for wind, just elevation to true. 2 spotters (me and Adam) out to 1600 using this method and it worked out really well. Most of the shooters we had never shot out past 300. Its effective and makes you look like you know what you're talking about if you can accurately gauge the wind.

 

[Deleted member 113831]

We did a shoot this last weekend with 5 shooters no kestrels for wind, just elevation to true. 2 spotters (me and Adam) out to 1600 using this method and it worked out really well. Most of the shooters we had never shot out past 300. Its effective and makes you look like you know what you're talking about if you can accurately gauge the wind.

What was the elevation where you were doing this?

 

[Mag1c-Mik3]

What was the elevation where you were doing this?

4800ish

 

[Rover31]

Is the wind calc/formula that was talked about in the podcast posted? If so could I get pointed to it?
Thanks

 

[Deleted member 113831]

Is the wind calc/formula that was talked about in the podcast posted? If so could I get pointed to it?
Thanks

There is a rather lengthy discussion of it here:https://www.snipershide.com/shootin...r-podcast-70-mike-and-frank-are-back.6891601/

But the general assumption is that the first number of your G1 BC is the full value wind that will push your bullet 0.1 mil per 100 yards for 1 mil at 1000 yards. This is referred to as your "mil wind" or "basic wind".

If you are at 2000ft (28.0Hg) and 2800fps this is where this works the best. If you are at 2600fps subtract 1 from that first BC number. If you are at 3000fps add 1 to that BC number. There are smaller adjustments for elevation, 0.5 per 2000ft. So at sea- level subtract 0.5 from that first G1 BC number. At 4,000ft add 0.5 to that G1 BC number.

If all you have is a G7 BC number, then multiply that number x2 and go from there. That will be plenty good enough for this purpose. Ex. 0.270 G7 x2 = .540 G1.

 

[BallisticPrimate]

FYI this system works well with G7 BC's and meters per second wind ?

 

[christopher.dow]

I’ve read both threads on this and have created a spreadsheet to help me understand it. I’ve “tested” it against Trasol (the only app I have that separates spin and wind drift). It lines up pretty well, meaning it can be off by .1 MRAD, but on steel targets at match ranges, you’ll get hits (IFF Trasol is correct).

Here’s the link:
https://docs.google.com/spreadsheet...YrdMXUgd8b52kKqnw01XU/htmlview#gid=1495566687

You don’t have to be logged in to Google to look at it, but you will have to log in to copy it to your Google Drive. Otherwise, you can download it in a number of popular spreadsheet formats.

I hope you find it as useful as I do. @Skookum & @Lowlight let me know if you see any problems with it.

 

[Deleted member 113831]

I’ve read both threads on this and have created a spreadsheet to help me understand it. I’ve “tested” it against Trasol (the only app I have that separates spin and wind drift). It lines up pretty well, meaning it can be off by .1 MRAD, but on steel targets at match ranges, you’ll get hits (IFF Trasol is correct).

Here’s the link:
https://docs.google.com/spreadsheet...YrdMXUgd8b52kKqnw01XU/htmlview#gid=1495566687

You don’t have to be logged in to Google to look at it, but you will have to log in to copy it to your Google Drive. Otherwise, you can download it in a number of popular spreadsheet formats.

I hope you find it as useful as I do. @Skookum & @Lowlight let me know if you see any problems with it.

The values listed in the table aren't going to work much past 1000 yards.

By making the wind equal to 1 mil at 1000 yards, you are basically "truing" that wind drift. You are taking small errors and amortizing them over the whole 1000 yard distance. Once you go past that, the differences add up very fast. Past 1000 yards, each 100 yard line is worth something close to 0.2 mils instead of 0.1 mils.

The sleeker and faster the bullet, the further you can push it past 1K, but by the time you get to 1300+ yards, it's just not going to work without additional windage being added.

 

[Timetoshoot]

I have limited experience using this system, yet am liking the simplisty and have good results so far. Looking at electronic predictions and actual wind dope for a high BC FAST ROUND I’m using 6.5 mph for .5mil at 500. 1mill per hundred works to 800yrds. It jumps .2 @ 900 then .1 increments till 1200. Then .2 increments for 1300 and 1400. Haven’t had the opportunity to shoot it past 1425.

It has helped me to create a reapatable workflow for dealing with wind.

• Use kestrel at shooting position to identify high and low trend.
• Look for evidence to confirm similar wind direction and velocity down range.
• How will terrain influence wind.
• Pick a number shoot, observe impact
• Believe the bullets, adjust, hit target!

I m using a wind only table based on this method for windage. I have wind set to zero and direction zero on any electronics. At distance I will substract or add .1 or .2 very heavy wind.
Im being more successful using this system. Im sure some of it is fact that I have a system. Some is the ‘science’ of find a mph that matches .5 at 500.

Thanks Frank, Mike, and all here for providing a clear description to help blend art and science of reading and doping the wind.

 

[christopher.dow]

The values listed in the table aren't going to work much past 1000 yards.

By making the wind equal to 1 mil at 1000 yards, you are basically "truing" that wind drift. You are taking small errors and amortizing them over the whole 1000 yard distance. Once you go past that, the differences add up very fast. Past 1000 yards, each 100 yard line is worth something close to 0.2 mils instead of 0.1 mils.

Yeah, the spreadsheet turned out to be useful only for trying to figure this out. After listening to the podcasts several more times and trying a bunch of stuff in different calculators (4DOF, AB, and TRASOL), this is what I’ve come up with for my 6.5s:

Fiddle with 90° wind values until you get .1 mil progressions to 600 yards. Then look at what happens. For my 6.5 Berger AR Hybrid OTM Tactical load, it’s 6 MPH. That jumps .2 at 700, then .1 to 900, and .2 per hundred yards after that until you get past the round’s effective range. This is easy to remember. The table looks like:

100: .1
200: .2
300: .3
400: .4
500: .5
600: .6
700: .8
800: .9
900: 1.0
1000: 1.2
1100: 1.4
1200: 1.6
1300: 1.8
1400: 2.0
1500: 2.2
1600: 2.4
1700: 2.6
1800: 2.8
1900: 3.0

So, I think I can take an estimation and wind value and feed that into this in my head to get the a wind call.

For my 300NM using Warner 198s at 3050 fps, its a bit weirder, but I think it can be managed.

I’ll have a chance to try all this out on Friday.