Help needed for trajectory and windage

[wildcat westerner]

Good, I needed to know that!
Now, this is the way Brian Litz does it. He only used 1 mph at 90 degrees and then multiplies by the wind speed. Thus its easier and quicker to deal with wind switches. Thus, one mph at 1200 is just 6.3 inches, correct? That's in incredibly small amount of displacement for this bullet, for such a long distance, is it not?

WW

 

[bigngreen]

To be honest most of us have programs on our smart phones that generate the correction. I have lost the math a long time ago being reliant on tech.
To manually do it I'd have to dig out some feild charts in my shooting log book.

If your posting from a computer you can us JBM ballistics on line and generate yourself a chart. Works very slick!!

 

[dfanonymous]

The math is based on BC and mrad.
It doesn't work as well in MOA but it's still doable.

Find the wind that matches your up with the BC.
So if you have a g1 of .427, find the wind that is .4 mils.

Let's say that is 5 mph, we say that's a 5 mph gun.

It's would look like:
5 mph wind
100y .1
200y .2
300y .3
400y .4
500y .5
600y .7
700y.8

The skip in the numbers is not a typo. It's an adjustment for BC degradation and bullet velocity retardation.

To do moa involves more of a headache.

You do the same, find your BC/wind number but subtract it by 1. Is if you had a 5 mph gun on BC, you have a 4 mph gun on MOA. It would be
yards @4 mph x .4=

So 5x.4= 2 moa for 500y.

This method is better than using military constants because most of you don't use that ammo, or .308s, or those service rifles. The constants are not designed for all things. This is. However the moa quickwind still has its issues with rounding errors and such you have to be aware of, and when to skip up for BC degradation and mach changes.

A kestrel is still going to be more accurate, but this is great for when equipment goes down, you can do this in your head.

 

[wildcat westerner]

I am trying t work with this. I can understand MOA. Assuming a cartridge is capable of 2,900 fps with a 212 gr. .30 caliber bullet with a G7 0f .336, how does this match up with your BC/wind number in which you subtract 1?

 

[dfanonymous]

I am trying t work with this. I can understand MOA. Assuming a cartridge is capable of 2,900 fps with a 212 gr. .30 caliber bullet with a G7 0f .336, how does this match up with your BC/wind number in which you subtract 1?

You need to know the g1 just for this. You can use the g7 for everything else.

Here: https://www.snipershide.com/shooting/threads/moa-wind-math.6917057/

I've never been great at explaining the MOA math. It's literally one of the reasons the military kicked moa completely. This has been around since as far back as I was doing this stuff and from the best I can tell, since the 90s.

I would learn the MIL method first. Makes it easier to know what you have to do. That's where the subtract 1 comes from. If you know your guns MPH already and you want to convert it to MOA, you subtract 1 from you mils method.

If you have no idea what I'm talking about then I would investigate quick wind to get you started.



Further broken down Barney style

Gun MPH Wind Bracket Rose

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[skipglo]

You did !!!!

The chart is in MOA so it's just over 63 inches of drift at 1200 if I did my math right.

 

[wildcat westerner]

Mathew and all others,

Wow, I have run into Palma shooters, who in their sleep know more about shooting in the wind than 99% of the other shooters put together. If your into Palma you must know of Trudy Fay, multi world champion Palma team member. I have gotten to know Trudy through Whittington and I NEVER could do what she does.! From my dealing with my patients I watched her and noted she does not move in prone, lncredibly strong arms for her slight build. Also, she has her eyes tested every 3 months. OK-enough of that.

I want to be able to utilize this heavy ELDX bullet in hunting situations in the latter portions of the season-Nov-Dec. when deer are migrating down the Rockies and the distances can be both short, in the Junipers; and very long ( I choose 1,200 yards) Thus we are potentially talking the shot of a lifetime, with potentially little time to rangefind ,and make the shot in the prone.

Everything I saw and read here is potentially is going to get me to the situation when I can see the game, make the distance estimation with proper inputs and using the .337 G7 ballistics data for this 212 grain ELDX bullet reduce the damnable effects of the winds here, to a more manageable wind hold. The BC of this bullet is so superior to the 165 grain bullets which I have used successfully since 2000, that it was only in shooting beyond 600 here that it became evident when shooting at a deer sized animal, wind drift was the premium for a clean hit. I have set Worlds Records at 600 yards. That was target shooting, and has virtually nothing to do with precise placement of the first shot when hunting.

That's the reason for trying at last to come up with an efficient plan to deal with range/wind estimation. When at Whittington a single day will be devoted to accuracy and velocity with this bullet. Then the 1,000 yard range will get a workout. I have never seen Whittington without winds on the 1,000 yard range and the practice in dealing with this bullet should provide me with some good practical knowledge about its strengths and limitations.
Thanks to all involved


WW

 

[lancetkenyon]

You are putting the cart WAY in front of the horse here.

If you don't even have a load developed, all these are totally hypothetical answers.
Do you even have the rifle set up?

 

[FEENIX]

You are putting the cart WAY in front of the horse here.

If you don't even have a load developed, all these are totally hypothetical answers.
Do you even have the rifle set up?

This!

 

[wildcat westerner]

Howdy Lance,

Its true the latest barrel is being fit to this rifle, but the cartridge was designed by myself and PT&G back in 2000 and developmental work was done at that time which showed the RWS brass superior in terms of strength to any other I had dealt with. I have not done any testing since despite building and selling rifles in this caliber to people who saw what I did on various ranges and were determined to buy them from me. Thus I ended up with deciding to build another and decided to concentrate on the 212 grain ELDX for potentially long range work here in the Rockies.
Last night Troy, from this site, helped me install and use the Hornady 4DOF system and explained to me what I had been inputting into other ballistics systems which was incorrect. This was huge to me.
So, I stand to go to Whittington with another experienced reloader and spend a day on the Coors range testing and reloading. The two ELDX bullets that are the best in my rifles preferred to be "into the lands" where they are very accurate. Thus, I won't be starting from scratch, will have access to 3 different chronographs and all the reloading benches inside at the Coors range that can provide me with instant alterations to my existing starting loads and let the 2-300 yard targets tell me about accuracy potential.

 

[Ken61]

I do it the old fashioned way. I find an "ideal" day, zero at 100 yds. Then put up claybirds ot as far as I want. Shoot the claybirds, record the scope setting, and I have a dope chart.

 

[eshell]

Taylorbok,

Huge thanks for what was almost certai9nly easy for you. According to your specs the 212 grain ELDX only drifts 5+inches at 1,200 yards in a 10 mph wind! Lord, that almost seems to violate known rules of physics!

Not 5.07 inches, but 5.07 MOA. MOA is a unit of angular measure that looks like a slice of pie when viewed from above. The further out one gets, the greater the distance subtended by this angle.

An MOA (minute of angle) is equal to 1.047 inches at 100 yards ONLY.

The chart is in MOA so it's just over 63 inches of drift at 1200 if I did my math right.

You did, and this is the correct answer.

One MOA = 1.047" (100 yard value) x 12 (the number of hundreds of yards) = 12.564" at 1,200 yards.
12.564" (one MOA @ 1,200 yds) x 5.07 MOA = 63.7"

 

[eshell]

I do it the old fashioned way. I find an "ideal" day, zero at 100 yds. Then put up claybirds ot as far as I want. Shoot the claybirds, record the scope setting, and I have a dope chart.

This is good, but to be complete, you'd also need to record density altitude to account for varying air density due to varying environmental conditions.

 

[Taylorbok]

if you want the 1 mph wind just move the decimal. That will be close enough