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Determining Wind Speed and Direction



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the most important part of long-range

shooting can be your ability to dope the

wind and determine what the wind is

doing not just where you're standing but

downrange in this week's shooting tip

we're going to teach you three

techniques that allow you to bracket the

wind and bring it into a quantifiable

attainable process that we can

systematically go through and achieve

but first I want to talk about a very

simple very easy concept that gives us

the ability to bracket our wind speed in

in in attainable values and also execute

these long-range shots and all it takes

is a little preparation in our cartridge

and bullet selection let's just do an

example and I think that'll illustrate

the concept a lot of people set up to

shoot long range and there they're not

quite sure what cartridge they're going

to pick the 308 Winchester has a lot of

connotation of being a military tactical

long-range shooting round let's take

that cartridge with a 168 grain

hollow-point boattail bullet and compare

it against a seven millimeter Remington

Magnum with 168 grain Birger vld very

high ballistic coefficient with the 308

at a thousand yards in a 10 mile an hour

wind we have about nine minutes of angle

of wind deflection now that's 90 inches

compare that against the seven

millimeter Remington Magnum

that's 168 grain bullet just over 3,000

feet per second we're talking four and a

half minutes of angle or 45 inches

that's half the wind deflection now

think about that for a minute what that

means is if you shoot the 308 Winchester

you have to be twice as good at doping

your wind so that you can make that shot

make that compensation and and be the

long-range hero of the day if you're

shooting the 70 millimeter Remington

Magnum it allows you a little more

margin of error in your ability to dope

the wind and consequently your point of

impact and your hit probabilities come

so if recalls an issue take that same

concept of efficient bullet and adequate

velocity and look at like the 65 to 84

with the 140 grain bullet again high

ballistic coefficient adequate velocity

reduced wind deflection now what we're

going to take this information and and

spin it and turn it into a technique

that allows us to systematically analyze

our conditions and dope or determine our

wind speed and direction and with that

information we can execute a proper

ballistic compensation in a lot of

long-range shooting situations your

success is going to be based solely on

your ability to determine your wind

speed and direction and make a proper

wind compensation now we're going to

cover three really simple techniques

that allow us to apply a bracketing

technique of estimating our wind in 0 5

10 15 mile-per-hour increments and with

the right cartridge combination this is

going to put you on target in the vital

zone now the first technique is really

simple we've covered this before it's

using a hand-held wind meter if I'm set

up with my spotting gear and equipment

and I've got my shooter beside me and

I'm looking at some of our other

indicators to the scope looking at the

target I've also got my wind meter up

here automatically measuring the cross

wind speed and then obviously we can

determine the direction because we're

standing right here

so I'm measuring crosswind speed while I

analyze my target and I'm looking at the

wind meter and kind of running an

average on on how fast that winds

blowing again only the cross wind

component is measured there now this is

a very simple technique but it's

limitation is it's only telling us what

the wind is doing right here where we're

standing and in a lot of situations the

wind across the canyon or down in the

valley is going to be completely

different than the wind that we're

measuring right here so we need some

more techniques now the second technique

is I feel the most useful the handiest

probably the most applied technique that

we have in our arsenal when we're out

shooting long

and whether it's in the field or on

targets or shooting schools etc and

that's Mirage analyzing the Mirage or

the heat waves which are caused by

atmospheric distortion because of

differences in the ground and air

temperature now what we're looking for

is wind speed and direction so let's

start with a no wind condition

we've got mirages downrange we see it in

the scope and it's boiling straight up

that tells us that we have no left or

right component and it also tells us

that there's zero wind speed so zero

mile-per-hour wind speed that indication

can show whether it's dead calm or if we

have a headwind or tail wind so if we've

got a ten mile an hour tailwind and we

look through our scope we're going to

see that vertical mirage that tells us

that Mirage automatically quantifies or

calculates the crosswind velocity only

so it automatically tells us only the

crosswind speed so let's look at a

couple different variables let's look at

a five mile-per-hour wind if we're

looking downrange through our scope and

we see that Mirage tip over to the right

at a 45 degree angle what that tells us

is we have a left to right wind and a 45

degree angle also tells us that we're

about a 5 mile per hour wind so we take

that value let's do it one more let's

look at 10 miles per hour that would be

a horizontal wind or 90 degrees if we

look down range we see horizontal wind

90 degrees that tells us left to right

wind it also tells us it's at least 10

miles per hour now the at least is the

kicker here because higher wind speeds

still indicate with a horizontal Mirage

so we have to be careful it also makes

the wind meter more applicable in those

higher wind speeds usually higher winds

mean more consistent winds so the wind

meter becomes a more effective tool in

analyzing the direction now the way that

we see mirage is using high-power optics

whether it's a spotting scope or a rifle

scope this is one argument for using a

high magnification rifle scope is it

allows us to zoom in

analyze and detect that Mirage now we

could zoom in on our target or we can

zoom in on a point say halfway to our

target analyze the Mirage at that point

and then use that in our summation of

what the wind is doing so the last

technique is kind of a double check we

take our wind meter value and we take

what we've seen in the spotting scope or

our rifle scope for our wind speed and

direction downrange and then we double

check with analyzing vegetation and I'm

talking about looking at grass leaves

you know watch the trees swaying watch

the push on the trees even little things

like looking at an insect hatch or seeds

that are floating across your line of

sight or spider webs up in the mountains

and you'll take these indications and

confirm that direction and magnitude

that we've estimated using our wind

meter and using Mirage now these three

techniques combined are going to make

you a more efficient shooter and

combined with the right cartridge

combination and systematically applying

that bracketing technique you'll be able

to execute those long-range shots making

a proper wind compensation I'm Aaron

Davidson for more shooting tips go

online to long-range pursuit calm