Wind and Dope charts (and getting boned by assumptions)

[milotrain]

I was reading through "The Wind Book for Rifle Shooters" and decided to rebuild my wind charts. Most of my charts are interpolations of some rules of thumb, and I finally decided to actually use the JBM calculator to figure out what sorts of drift I'm seeing at various ranges and wind speeds. This was eye opening because most rules of thumb seem to be far from my calculated numbers. They will get me on paper but they won't get me near the bull.

The second "ah ha!" moment was when I realized I could combine the dope card with a wind value diagram. In this way it's a much more physical device than just a card of data. I like how it finally worked out so I figured I'd share it. At some point tomorrow I'll remove my data and post a blank card if people want to use it. Those four colored pens are good for this sort of thing.

The chart is in MOA, the clicks at the bottom for the drop chart are in 1/4 MOA clicks for typical NM sights.

[BillyGoatCrawler]

While I find this interesting, good luck. Refer to my trigonometry thread and see how that went with people's responses. It's a tough crowd here.

But, I do like the idea and might manipulate my own version.

[milotrain]

I feel you standish! The big surprise to me was how much off rule of thumb was from calculated drift. I appreciate your thread it got me started on the path of rebuilding my charts.

[BillyGoatCrawler]

I feel you standish! The big surprise to me was how much off rule of thumb was from calculated drift. I appreciate your thread it got me started on the path of rebuilding my charts.

You make me smile, man! You understood my take home. I remember when first learning of wind corrections being told the full value/half value style clock methods of how wind affects a projectile. Those aren't very accurate. This makes the rule of thumb more accurate and organizes it more effectively while giving more information than a standard table of full value wind at 10 mph.

Of course actual drift is going to vary because of multiple wind vectors, but I will make one of these up for .308 175 gr since that is the most common round I see used by newer LR shooters.

Looks like a very good way to start a new shooter on wind. From there, they can get experience and see how real world affects it. Better than just saying "reading real wind is an art." and leaving them at that. This gives a base to start at and gain experience from.

I think the variation I will make will have graduated ranges in place of where you have the wind column on the far left. Then in each clock section of wind value, I will have those three columns be wind. Each column will have a different wind velocity to choose.

What program did you use to create this?

[highpower790]

I like it Milo,but for me it all comes down to a little swag...scientific wild *** guess!

[milotrain]

This makes the rule of thumb more accurate and organizes it more effectively while giving more information than a standard table of full value wind at 10 mph.

Of course actual drift is going to vary because of multiple wind vectors, but I will make one of these up for .308 175 gr since that is the most common round I see used by newer LR shooters.

I think the variation I will make will have graduated ranges in place of where you have the wind column on the far left. Then in each clock section of wind value, I will have those three columns be wind. Each column will have a different wind velocity to choose.

What program did you use to create this?

That's exactly right. I get while the rule of thumb is the way it is but I shoot 5.56 service rifle so the 150gr ball dope doesn't really work. I only shoot those loads and at those distances so it seemed to make sense to organize it the way I did, but if you are just using one load it makes WAY more sense to have an incremented yardage column. I've been reading this book lately and it clarifies a lot of stuff that I didn't understand. Really excellent book.

I drew this three or four times before getting pissed off at my various drawing programs and buying a 1month subscription to AutoCAD. I learned to draft with it in college and when I need exact control of layouts that's what I use. It isn't "fast" though



I understand Joel, and I appreciate the "no log method". I feel like I will get to a point where I ditch the log, but I realized I needed some mathematical dope because I just don't get on the range enough to get a sense of the wind. I know you don't forget this but you've been looking through glass at 600 for more aggregated time than I've been holding the service rifle.

[highpower790]

Milo if ever there was enough time I would be happy to help you.I think it would be interesting to have a coach and a shooter side by side using your chart.You would be the only one using your chart and the coach just does it by experience...Both would be looking through scopes to see mirage,and looking for the same things before taking a shot.
Jim does something similar at Coalinga when coaching the kids.

[milotrain]

That would be amazing. I'll PM you.

[BillyGoatCrawler]

if you are just using one load it makes WAY more sense to have an incremented yardage column. I've been reading this book lately and it clarifies a lot of stuff that I didn't understand. Really excellent book.

I drew this three or four times before getting pissed off at my various drawing programs and buying a 1month subscription to AutoCAD. I learned to draft with it in college and when I need exact control of layouts that's what I use. It isn't "fast" though

I ripped off your idea and made a much more generalized version and created a new thread. Man.... I used paint.net to create mine. Talk about a long process. Making concentric arcs with a cheap program is a nightmare.

I'll look into that book, but if I am doing any reading these days it's for the courses I am in...

[milotrain]

Standish, get the book. I'm on page 34 and my mind is blown.