Looking at the Daily Bulletin

[Rustystud]

I looked at the Daily Bulletin Weather Station with keen interest. I find myself to be a techno gadget person. I have not looked at the F-Class rules so I don't know about its use in a match. I think if it is behind the firing line there is no issue.

My general thoughts are the conditions at the muzzle have little to do with the conditions at mid flight and post mid flight where the wind has the most effect. I generally pay more attention to mirage off the face of the target and the wind flags toward the end of the course.

Having seen the flags blowing in differenet directions or at different levels of intensity at different distances at the same time causes me to pay less attention to the closer flags and signs.

Gene Beggs has a device called the wind probe. It looks at wind more relatively than any other device I have seen. Gene frequents the BRC web site maybe he will see this post and chime in. Gene is a retired pilot and thinks wind and bullet slip stream like a plane flying through the air.

My thoughts are that it is great to know what is going on with the wind but one needs to know what the wind is doing down range more than at the line.

Rustystud

 

[jb1000br]

Nat - wind closest to the muzzle has more effect than that near the target...more time to affect change...bullet is headed off course early in its journey and continues that way.

JB

 

[Cheechako]

JB is correct, as usual. Wind closest to you is more important than wind nearer the target. Once that bullet changes course due to wind it doesn't come back in line. Many short range benchrest shooters will put their first flag as close to the bench as they can. The Probe is a great wind velocity indicator but tells you nothing about direction so it has to be used in conjunction with a regualr flag. JMHO

Reading ALL winds is important. But there are some more important than others. That's what seperates the good shooters from the other guys, like me.

Ray

 

[Rustystud]

I am no expert on the wind an have my ears open to learn something new every day. I see your logic but the bullet is moving faster and with more energy the first half of the course than the second half. Does your logic apply to both short and long range shooting equally. I see identical bullets shot at 600 and 1000 yards. For sake of this question the wind conditions are also identical. The bullet time in flight is about double for the 1000 yard shot. Therefore the wind influence would also be about double. The energy the bullet has left after 600 yards drops off exponentially. I know my hold off is more than double for 1000 than 600 yards. I can also say my hold off for 600 is greater than 100 yards. That to me tends to refute your theory. I do agree any deviation at the front end will be amplified at the tail end.

I would think being able to judge the wind one would have to make good judgements at both ends of the course. eh

Rustystud

 

[Cheechako]

Rustystud

I'm not very good at explaining complicated stuff such as ballistics but let me try to touch on a couple of your points.

First of all, bullet energy is not a factor. Only BC and velocity are. Otherwise the big 338 bullets with their weight, sectional density, and energy, would exhibit far less wind deflection than a 6mm, something that we know is not true.

Second, it is true that the time of flight for a bullet to 1000 yards is twice what it is to 600 yards but the time from 600 to 1000 is actually less than it is from muzzle to 600.

Velocity near the muzzle is faster than it is at the target but the effect of the slower velocity is not as great as you would imagine because it is really the delay and not the velocity that is the more important factor. That's why a supersonic 22LR bullet will exhibit greater wind deflection than a subsonic target load.

The best way to show the greater effect of the near wind vs the far wind is to imagine a 1000 yard range that is calm. A bullet fired will show no wind deflection. Now, a 9 o'clock wind at x mph blows between the muzzle and 50 yards downrange. The remainder of the range is still calm. Let's say that wind deflects the bullet 2 inches at 100 yards. At 1000 yards the deflection will be 20 inches, even though the bullet travelled through calm air for 950 yards. Now say that a 9 o'clock wind at x mph is blowing between the target and 950 yards but the remainder of the range is calm. The deflection on the target would be only 2 inches. The bullet travelled through an identical 950 yards of calm and only 50 yards of wind but the deflection was only 1/10th as much.

Unfortunately, things in real life are never as simple and the wind doesn't blow consistently over a 1000 yard range. That's where flags, and an ability to read the different conditions make all the difference between winning and first loser.

I hope somebody else will jump in here and explain this better than I can.

Ray

 

[butchlambert]

Nat, listen to Ray. He knows of what he speaks.
Butch

 

[rstreich]

I think you summed it up pretty well with your last example, Ray. The wind that creates a 1-MOA deflection in the first 100 yards is the equivalent of a wind that creates a 10-MOA deflection in the last 100 yards--if the bullet were still travelling at the same velocity. If you assume that an average match bullet is travelling at worst 40% as fast for its last 100 yards as it is for its first 100, the wind must be 4x greater for that last 100 yards to cause the same deflection as the wind for the first 100.

...Second, it is true that the time of flight for a bullet to 1000 yards is twice what it is to 600 yards but the time from 600 to 1000 is actually less than it is from muzzle to 600....

Somehow I don't think you mean what you typed here 'cause the math just doesn't work out.

robert

 

[Rustystud]

Butch and others:

I am not arguing just trying to be logical.

I was told just the opposite at the long range firing school.

I have paid more attention to the flags at mid course and end course than up close.

I learn sometning every day.

Thanks for the enlightenment.

Rustystud

 

[vmthtr]

Reading the Extreme Accuracy book says the opposite. As velocity drops the wind has more effect. Who is right? I, also have always thought that the wind effects the bullet more at the muzzle, until I read the book.

Mike

 

[rstreich]

The wind does have a greater effect as the velocity drops, but you have to factor in the remaining distance to the target. One MOA of deflection means just over 10" at 1000 yards, but one MOA of deflection at 500 yards only means 5" when it gets to 1000.

The problem with these examples, however, is that they take place on ranges where the wind blows over only one section of the range. In reality, it is not at all uncommon for the wind right at the firing line to be completely out of sync with the wind over the rest of the range. So, you could have a full-value 10-MPH left-to-right wind at the firing line, but varying values of right-to-left over the rest of the range. This could be why some shooters give more credence to the wind flags away from the firing line.

On a different note, I just got a chance to look at the Daily Bulletin. It's a neat idea, but I wonder just how much wind it would take to blow your scope stand over with one of those on it.

 

[jb1000br]

Hey Nat...another thing to consider...RE: those mid-range flags,on a 1000yd range) ...your bullet is probably flying way above them...unless you have some taaall flags.


JB

 

[M700]

Our dad-gum range has one heck of a canyon between the 300 & 500/600 yard targets... Two problems with that:

1) The wind going up or down that canyon is likely quite different than what's happening on the firing line, or at the targets.

2) Makes it a little tough to get a good 400 yard zero... A target would have to hover out there somehow.

It's the wind in that canyon though that can make the 600 yard line such a booger at our matches. Sometimes we get a calm day, but it doesn't last. Read it as best you can, launch 'em and pray.

FWIW, Guy

 

[jb1000br]

Guy:

2) Makes it a little tough to get a good 400 yard zero... A target would have to hover out there somehow.

good stuff! lmao!

 

[memilanuk]

Reading the Extreme Accuracy book says the opposite. As velocity drops the wind has more effect. Who is right? I, also have always thought that the wind effects the bullet more at the muzzle, until I read the book.

Mike,

I read that also... and I've also read The Wind Book,addresses mulitple areas concerning wind reading, effects and strategy, and quotes answers from,at the time) top competitors in long range High Power & Fullbore), and Prone & Long Range Shooting by Nancy Thompkins-Gallagher, which also contains a lot of detailed information on wind reading and effects. Both fundamentally disagree with that specific bit of what Ratigan says.

Who do you believe? Someone who has won top honors in the world of point-blank Benchrest as well as competes on the US World Benchrest Team, or people who at the top of *their* game in long-range High Power & Fullbore, including people who compete and *coach* the US Palma team? I have my prejudices, based on what sport I currently compete in, but I'm not ready to write off the other point of view. I'm reasonably sure it's not something that he,Ratigan) just pulled out of a hat.

I wonder if the difference in effect might have something to do with the kinds of bullets being used? Short flat-based custom benchrest projectiles, optimized for accuracy first, everything else second... vs. long, pointy VLD bullets optimized for B.C. first, accuracy second,I know some will object to that, but if they were optimized for accuracy, they'd be shaped like the point-blank BR bullets...) which tend to retain their velocity,both forward and side-to-side) better...

I'm no expert, but it is an interesting dispute!

Monte

 

[Cheechako]

...Second, it is true that the time of flight for a bullet to 1000 yards is twice what it is to 600 yards but the time from 600 to 1000 is actually less than it is from muzzle to 600....

Somehow I don't think you mean what you typed here 'cause the math just doesn't work out.

robert

Robert

Yeah, it even confused me. Here's what I was trying to say, using ballistic figures for a Berger 105gr VLD at 3100 fps:

Time of flight 0 to 600 yards = .695 seconds
Time of flight 600 to 1000 yards = .634 seconds
Total time of flight 0 to 1000 yards = 1.329 seconds

Monte

I think you're on the right track. As far as I know, Mike has never shot long range benchrest. His experiences and observations are probably limited to 100 and 200 yard,with a little 300 now and then) using the low BC bullets typical for those yardages. He's a great shooter, BTW, and I certainly would not discount anything he says.

Ray