# What about wind

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Mikecr, Aug 2, 2013.

1. ### MikecrWell-Known Member

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4,264
Joined:
Aug 10, 2003
The affect of wind on trajectory is a mystery to me. Maybe a challenge to IQ, or maybe to perspective.
I've read great discussions on wind drift-vs-deflection in causing trajectory displacement, and seen a few working rules of thumb. Yet they all seem(to me) to fail tests.

The working formula amounts to actual crosswind value for a given flight time lag.
D = W*(T-Tv)
This is not WIND*TOF, it's wind*time lag, and this is where tests seem to fail.

Time lag within any iteration of flight varies. Most of it occurs nearest the muzzle, as this is where drag is highest(even while higher in drag coefficient) and velocity drops at the highest rate. So time lag between 50-100yds is way different than time lag between 900-1000yds.
Yet this formula works from muzzle to any distance.

My questions:
In a 1kyd shooting session,
Does the formula work if actual crosswind is only applied in the first 100yds?
Does the formula work if actual crosswind is only applied in the last 100yds?
If there where both wind only in the 1st 100 AND last 100, do separate departures from flight path(in MOA) add up correctly?
That is for example; 'deflection' 1st 100yd of 2moa + deflection last 100yd of .3moa = 2.3moa of wind effect from muzzle to 1kyd.

Is this really why near wind is dominant over far wind?
Or is it just a matter of early deflection in moa applied the rest of the way?

Really, how is it that lighter/lower BC bullets at higher velocities would see less displacement from wind, while producing higher time lag(greater velocity loss rate) all the way?

Think about it & thanks for your perspectives.

2. ### BeluebowWell-Known Member

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107
Joined:
Dec 6, 2004
I'm not smart enough to answer your question's.But I am smart enough to know from all your posts/advice that Ive read I need to be paying attention to this thread.I believe this to be a good thread and one we all could learn from.