Measuring windspeed by dropping sand

I confused on those numbers.

Anyway, the proper way is to drop and item or look at a range flag.

The item will drift a certain amount. Point at the item, determine the angle of your arm while pointing. Divide that angle by 4 and it will give you the MPH.

The same with a range flag, determine the angle its flying. Stright down is O degrees, straight out is 90 degrees. Divide that angle by 4 and it gives you the MPH.

Here is a windage chart to show examples.

Wind%20Diagrams.jpg
 
Those diagrams do look more detailed than anything Ive been in contact with. Current USMC range books have the simplified diagram, and the whole practice of dropping a piece of paper or something and measuring the angle at which it hit the ground has been edited out of the book.
 
Actually I remember re sorting the same load-wind deflection info into a wind calculator before. What you have there is just an old format.

(Im talking about Creedmoor type wind calculators)
 
Where's the dope for the 75mph crosswind???
Click to expand...

To get the dope, you need a constant. The constant for the M1/M14 using Ball Ammo is 15.

You multiply the wind speed X the yardage (in 100 yards) / constant.

Soooooo Lets say your shooting 600 yards.

75 * 6 = 450

450/15 = 30 full minute clicks.

Or 7.5 target frames

( I think I figured that right)
 
Ervin:

Trying to calculate the wind's miles per hour is fruitless. Keeping a log book on range contitions and their horiizontal bullet deflection is most important. Watch the wind's effect on the bullet by logging conditions for each shot. That means watching tobacco smoke, rippling leaves, blowing grass, its feel on your face or anything that you see when you are shooting. By identifing conditions that you have previously seen you can make the proper sight move. When I was shooting of several Marine Corps' rifle teams that is the way that I kept my log book.

Semper Fi.

Gunnery sergeant
Clifford L. Hughes
USMC retired
 
If you are worried about wind, I assume you are shooting at more than 200 yards. I contend that by knowing the wind speed and direction at the fireing point is just about useless - what is much more important is what is happening down-range. There may be little relationship to what your feel on your face. I say, Maybe the last 25% of the distance to the target is the most crucial area, when the bullet is moving slower.

A decent scope will often let you read that wind by seeing the mirage waves. And somebody help me, I think they disappear when the speed gets up to 10 mph or so. But then use the scope to look at the grass and weeds in front of the target.

If you are on a range, the official NRA windflags are "calibrated" to give reasonable accuracy of the wind, at there location.
 
thanks Gunny I'll keep that in mind.

The range I shoot at has unpredictable wind and the flag is of very very little help. So every little trick is useful, but the comment about wind reading at firing point has convinced me not to bother with a Kestrel wind reader.
 
Anyway, the proper way is to drop and item or look at a range flag.

The item will drift a certain amount. Point at the item, determine the angle of your arm while pointing. Divide that angle by 4 and it will give you the MPH.

The same with a range flag, determine the angle its flying. Stright down is O degrees, straight out is 90 degrees. Divide that angle by 4 and it gives you the MPH.
Click to expand...
That's the way I learned it as well.

There's a great Army training video from what looks to be '40s or '50s on marksmanship with the M1 Garand, and the instructor explains the technique pretty thoroughly in it. Go here and download the "Rifle Marksmanship with the M1 Rifle Part 2" flv file. You'll need RealPlayer or something similar to play it, so you may need to download that as well, but it's worth the trouble. Part 1 is great too, but IIRC, it mostly deals with shooting from the positions and sling use. Anyway, if you go to 6:45 in the part 2 video, that's where he begins explaining windage. At around 13:30 he goes into the method that kraigwy mentioned above, and how to apply that to make corrections in your windage.

Jason
 
Determining wind speed by dropping sand or anything else is a guesstimate at best. Does give you the direction though. Mind you, the wind can be different at the shooting point and the target.
 
Wind

I contend that by knowing the wind speed and direction at the fireing point is just about useless - what is much more important is what is happening down-range.
Click to expand...

+1 about that. A wind gust at my point tells me that there is a wind gust at my point. I can infer from that that there is probably one at the target but not necessarily so and not necessarliy the same gust.
One of the ranges that I shoot at is set in a horseshoe shape of berms and hills with the targets at the foot of the U. It is not unusual to have wind gusts at the targets blowing in a different direction than at the firing points.
Pete
 
Attached is a link to the Camp Perry Windchart. It goes to 75 MPH.

http://usarmorment.com/pdf/cpwind.pdf

It really blows there, on the edge of Lake Erie.

The next day after a bad Camp Perry wind day at Long Range, I was in the pits complaining about how bad the wind.

This grizzled old guy pops out a couple of points away and tells me the wind the day before was nothing. "When I won the 1000 yard match for the USMC team, I had full left windage and was still aiming three target frames over" :eek:

It is my recollection that the rear sight on a M14 has 33 MOA of windage. Given the target frames are at least 9 feet between centers, that was one windy day!

Rodriquez Pitts, Camp Perry Ohio

Rodrequez2011target69.jpg
 
Most ranged have flags through out the range. If flags vary (and they will) you use the flag at the center of the range if you can't read mirage.

When flag vary, then its best to use mirage. When mirage gets to the point where its no longer readable, (about 12-15 MPH), then the wind is normally constant throughout the range and you can go back to the flags.

Sure its an estimate, but its the best estimate we have. No to people will read wind the same, no two sets of eyes are the same. It take experience, like anything else experience is the best teacher.
 
Are you dropping dry dust, or fine granite? From what height are you going to see a deflection? Is the sand dry or moist? Not sure if I buy into the idea of a table without some coefficients, which you can probably discern by observation anyway.
 
Determining wind speed by dropping sand or anything else is a guesstimate at best. Does give you the direction though. Mind you, the wind can be different at the shooting point and the target.
Click to expand...

It is, but it gives you somewhere to start. And you can use your estimate that you make up close to gauge what it's doing downrange by looking at similar visual clues (grass or leaves blowing, etc.). It's anything but exact, but it's better than a WAG.

Jason
 
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