How do you judge wind

[wjm1000]

I've been hunting and shooting long-range for around forty years and this is my thoughts on judging wind, First off I feel the wind closest to the shooting position is the most important. The reason I say that is, as the bullet exits the muzzle of the barrel two major factors act on it immediately, gravity and wind along with other environmental factors but I think gravity and wind are the most significant. A few thousands of movement at the muzzle can be huge at 1000 yards. Having said that as the bullet moves along it's flight path it can be and will be influenced by other whim's of the wind. What I do to judge the wind at different yardages is use the parallax to get a rough idea what the wind is doing at those yardages, as the bullet gets further from the shooting position and closer to the target the less important it becomes until I totally ignore what the wind is doing at the target because the bullet is already there. I'll watch the trees, grass and if there is any mirage I'll note the direction and speed that the mirage appears to be moving,

This is a very broad view of wind reading and just some of the basic things that I take into consideration. There is an article on one of the other forums by Shawn Carlock that goes into much more detail.

Before the advent of the kestrel this is how I judged the wind speed.
MPH Calm Smoke rises vertically
MPH 1-3, smoke will show direction of wind movement.
MPH 4-7, you can feel the wind on your face, leaves rustle.
MPH 8-12, leaves and small twigs in constant motion.
MPH 13-18, dust will stir up, tree branches will be in motion.
MPH over 19 and up I usually wont shoot unless constant.

 

[Coyotefurharvester]

I look at the last 25% of bullet travel as the most wind defection, since time of flight is apart of the calculation.

 

[K22]

I am earnestly trying to learn but haven't come close yet to mastering it. I watch weeds, trees, etc. Read a lot about it.

What has worked for me is I try to time the shot for breaks in the gusts. I know that probably won't work if you're in a timed competition match and I've occasionally had to let ground hogs walk, but it's worked for me several times.

 

[wjm1000]

I look at the last 25% of bullet travel as the most wind defection, since time of flight is apart of the calculation.

Time of flight is definitely part of it and as such the instant the bullet leaves the barrel and the wind acts on it and whatever movement it created on the bullet will be affected the whole time the bullet is in flight. The bullet will continuously be moving in the direction that was deflected. Say the bullet was moved 0.005” in one yard at the muzzle that would be 5” at 1000 yards. I’m not a math expert so my assumption my not be correct. Anyone out there that knows math please correct me if I’m wrong.

 

[Coyotefurharvester]

The bullet also slows as it travels down range, as it slows time of flight increase in incremental proportion. See --time of flight is longer between 100-200 yards than 0-100 yards, thus wind moves the bullet further off a straight gravity affected path.

 

[wjm1000]

The bullet also slows as it travels down range, as it slows time of flight increase in incremental proportion. See --time of flight is longer between 100-200 yards than 0-100 yards, thus wind moves the bullet further off a straight gravity affected path.

And it will also have more effect on the initial deflection.

 

[Tommie]

I studied wind deflection and got way into the weeds on the subject. For stationary targets at known distances with a chorus line of wind flags it’s all applicable. Insert swirling 20+ MPH gusts, moving targets, uneven terrain, random distances with no wind flags and the theory/calculations are out the window. Lots of sandbox time and developing a “feel” for the gun and it’s capabilities become paramount in this scenario. Maybe I’m subconsciously doing tons of calculations before pressing the trigger but ultimately I still am a Kentucky windage shooter. No laser ranging, no Kestrel and no dope chart. Wax on, wax off. Whatever.

Prairie dogs are fun

 

[Ned Ludd]

Near wind has the stronger effect in terms of total bullet deflection, not far wind. A near wind will move the bullet farther off line than the same wind closer to the end of the bullet's trajectory because once the bullet starts deviating from the original line of flight, it continues off course, even if no further wind acts upon it. The closer that effect occurs to the muzzle, the farther off line the bullet will travel by the time it reaches the target. Near wind has the stronger effect in terms of deflection, and it's not even close. Below is a nice illustration of how this works from the folks at Kestrel (from page 4):

StackPath

Something that may be a bit misleading in this figure is that the angles of both deflections (W1 and W2) appear to be the same. They are not because the bullet has slowed down by the time it reaches W2. Therefore the bullet under the influence of W2 would deviate at a greater angle from the line of flight than it would for W1, as I have shown using the red dotted arrow. Nonetheless, the total deflection for W2 will still be less than for the near wind, W1, because of the extra distance the bullet travels offline after the intial wind effect.

 

[marchx]

After reading Bryan Litz's essay on wind "Where does the wind have the most effect?" I just gave up on reading wind methods indicated by OP. Therefore, I just use the lazy man's method: I use my Kestrel.

 

[6.5 forever]

Kestrel for wind speed. Enter direction and speed into my FURY AB and shoot!

 

[FeMan]

The wind at the shooter is the most important. As stated above, the importance of the wind value at any one point decreases as you get closer to the target, but they all matter. It is the weighted value of the total wind affect that you want to determine if you can.

How I determine the wind depends on what I am shooting (close/mid/long/ELR ranges, do I have flags, is it a range or terrain, etc.). I have worked for years to calibrate my face for the wind speed and can get within a mile or two up to 15 mph. I do look at mirage as well if/when its available but you need to be careful with mirage, as it can lead you astray at times or be absent in certain conditions (like across canyon shooting). I shoot a lot in natural terrain in the 1,000 to 2,000 distances, and at those ranges and use the wind speed estimated by feel as a base wind call. Then I look at direction to calculate wind cosine vectors and topography for wind shadows and compressions. I integrate all that into a weighted average wind speed and angle and enter that into my Kestrel. I do this in as many natural settings as possible throughout the year to hone my skills.

 

[gunsandgunsmithing]

For all intents and purposes here, a bullet doesn't move sideways unless acted upon. A wind at the first "flag" and zero wind the rest of the way will move the bullet essentially like this


-----------------\_____________________________________>>

The only force still at play after the bullet leaves the cross wind is lateral inertia. For a 10mph wind, that would be worth about 14.6fps opposed to roughly 3000fps of forward inertia. Yes, it will have a new course to it's new poi but I can't see how it will maintain an angular trajectory after the force of wind is no longer acting on it. If you've shot over flags much, you know that it's very common to have several flags going in different directions at the same time and that a steady crosswind is much easier to shoot predictably. So yes, if the bullet is subjected to a steady crosswind for it's entire flight, it may appear angular or curved in it's trajectory,

It didn't draw like I intended but I think it's good enough.

 

[JFrank]

I try to shoot long range, interesting that watching the grass move within the sight line doesn’t really tell me what’s happening at the flight line of the bullet, nor do I get more than a generalization from flags close to the shooter.
I could have multiple or switching winds coupled with speed variations the early or late flags just are not able to pick up. Stan Taylor always said that “wind is your friend” but I’m starting to like mirage a little more.

 

[Coyotefurharvester]

Here is a typical varmint shooting solution 50gr bullet .25 BC @3600 fps muzzle velocity
10 mph full value wind
0-100 yards 1" drift
0-200 yards 3.9" drift. Subtract out first 100 yard drift. Bullet drifted 2.9 inches between 100-200 yards.
0-300 yards 9.3" drift. Subtract out first 200 yards (3.9). Bullet drifted 5.4 inches between 200 -300 yards from muzzle. So 100-200 almost 3 times as much drift than 0-100. And over 5 times as much between 200-300 as the first 100 yards from muzzle.
MOA if angle is easier
0-100 0.9 moa
0-200 1.9 (100-200 1.0 moa) slightly more angle
0-300 3.0 moa (200-300 1.1 moa) angle has increased again.
I use a NOAA weather app(wind over layed on satellite image) and a kestral to confirm.

 

[gunsandgunsmithing]

Here is a typical varmint shooting solution 50gr bullet .25 BC @3600 fps muzzle velocity
10 mph full value wind
0-100 yards 1" drift
0-200 yards 3.9" drift. Subtract out first 100 yard drift. Bullet drifted 2.9 inches between 100-200 yards.
0-300 yards 9.3" drift. Subtract out first 200 yards (3.9). Bullet drifted 5.4 inches between 200 -300 yards from muzzle. So 100-200 almost 3 times as much drift than 0-100. And over 5 times as much between 200-300 as the first 100 yards from muzzle.
MOA if angle is easier
0-100 0.9 moa
0-200 1.9 (100-200 1.0 moa) slightly more angle
0-300 3.0 moa (200-300 1.1 moa) angle has increased again.
I use a NOAA weather app(wind over layed on satellite image) and a kestral to confirm.

True, but that assumes a constant wind over the entire bullet flight.

Bottom line...the flag that matters most is the one you didn't see change when you pulled the trigger.

 

[dcali]

I just wing it, because even with flags, I'm a bit hopeless unless it's a wide open range. But watching nearby tall grass is good, and trees further off can give you an idea of whether it's picking up or letting off.

But Ned is right - near wind matters more. Often, that knowledge is not very helpful.

 

[dcali]

Here is a typical varmint shooting solution 50gr bullet .25 BC @3600 fps muzzle velocity
10 mph full value wind
0-100 yards 1" drift
0-200 yards 3.9" drift. Subtract out first 100 yard drift. Bullet drifted 2.9 inches between 100-200 yards.
0-300 yards 9.3" drift. Subtract out first 200 yards (3.9). Bullet drifted 5.4 inches between 200 -300 yards from muzzle. So 100-200 almost 3 times as much drift than 0-100. And over 5 times as much between 200-300 as the first 100 yards from muzzle.
MOA if angle is easier
0-100 0.9 moa
0-200 1.9 (100-200 1.0 moa) slightly more angle
0-300 3.0 moa (200-300 1.1 moa) angle has increased again.
I use a NOAA weather app(wind over layed on satellite image) and a kestral to confirm.

What you're missing is that the drag force at the muzzle is much higher than down range. So when that early drag pushes on the bullet, it starts it on a path that will carry through all the way to the target. The wind near the target has less force and less time to follow through.

Think about wind 1 foot from the target. It's not going to matter at all. Wind at the muzzle will.

 

[Fairchaser]

Some other things to consider:

The wind closer to the shooter counts more at full value but less and less as the angle changes toward a head or tail wind on the bullet.
Spin drift will cause a left to right wind to increase the height of the bullet and vice versa.
There is a point where angle is more important than speed and vice versa depending on the wind speed.
Wind blows the scope image which must also be factored into the equation.
The sun will also draw the image towards it. As the sun comes over the target, the image rises. Clouds have the opposite effect.

 

[gunsandgunsmithing]

What you're missing is that the drag force at the muzzle is much higher than down range. So when that early drag pushes on the bullet, it starts it on a path that will carry through all the way to the target. The wind near the target has less force and less time to follow through.

Think about wind 1 foot from the target. It's not going to matter at all. Wind at the muzzle will.

I agree with this because higher velocity with a given bullet will have more drag...and drag is what moves the bullet.

Now, calculate all that when the flags are all going different directions and the clock is running. Lol!

 

[Bottom Fodder]

Ok let’s say to make it simple:
your shooting a 6mm 107 grain with a muzzle velocity 3000fps @1000 yards and you have a consistent true cross wind of 10 mph the full length going right to left
how much would that wind move the bullet to the left @ the target?