A little off topic. Someone on this board showed me a simple way to explain why we read winds 2/3 the distance to the target, LongRange. He was explaining to the Students why the wind effects the Bullet at this point more then any other .
He said "with the wind blowing, throw a ball straight up in the air, notice the wind will move the ball in that split second it becomes weightless" Thats why we read winds where the Bullet reaches it's max trajectory. Bullet becomes weightless like the ball. At this point the effects of wind overtake the effects of gravity.
This is also why the wind speed at your shooting position is of little importance. Thought this was a good analogy and always used it successfully. Of course I never give him credit for this analogy
If you don't have an answer for a Student for why his groups are all over the place. Need a little time to figure it out. A good one to use is "It's possible your Barrel Harmonics are off" Big word for something might be touching your free floated Barrel. Just like (PPIM) Pre Primer Ignition Movement. Jerking the Trigger.