I like the Vortex Optic's , The Vortex TMT (Trajectory Matched Turret) elevation cap is not just a simple BDC cap, it is truly custom-matched to your rifle and load. For maximum speed when adjusting for accurate long range bullet drop, nothing beats dialing a yardage marked elevation turret cap. No calculations are necessar, just simply range your target and dial the turret to the matching range. The Trajectory Matched Turret data is needed "Your Specific Rifle, Load, Temperature & Altitude Preference." Windage, long-range shooter estimates the wind, he looks at two primary factors 1st direction, 2nd speed. Observing the wind's direction is fairly simple and, is essential to calculating how the wind will affect your bullet in flight. Estimating the wind's speed is where the greater challenge lies. A traditional way of estimating windspeed is by looking around and seeing how the wind affects objects. A wind lightly felt upon your face is 3 to 5 mph, a 6 to 8 mph wind will agitate the leaves on trees, 8 to 12 mph and the wind is raising dust, 12 to 15 mph sways small trees, and water begins to whitecap at 17 mph. As bow hunters alot of us know this. Being able to estimate these with any accuracy requires practice. Personally I like wind meters & compass. I still like to to measure & use a compass to see were the wind is coming from, but also to evaluate my estimates. I make an estimate using the appearance of objects then employ my wind meter to see how accurate I was. When I'm wrong, I analyze the cause so I'm better attuned for the next time. Having made an accurate windspeed estimate and determined the wind's direction, you now determine how this will affect your bullet's flight. First, consider the line between your muzzle and your target in the context of a clock, with 12 o'clock being directly to your front, six o'clock directly to your rear, and 9 and 3 o'clock being left and right respectively we first consider the wind's direction. If the wind is coming from 12 or 6 o'clock it has no value because it will not drift "push" your bullet right or left, it has no significant effect! Winds coming from 9 or 3 o'clock, however, have the greatest or "FULL" effect. It's the oblique winds, coming somewhere between those four primary directions from, say, 10:30 o'clock or 4 o'clock that can be the most perplexing because it only takes a slight direction change to significantly increase or decrease the wind's effect. A rough rule-of-thumb is that winds between the four primary directions are half-value, according to many sources, however it has been my experience & from others I've talked with that oblique winds halfway between FULL and No compensation are more deserving of a three quarters value. These "oblique" angles are where wind estimation or "doping the wind" assumes as much art as science. How to compensate, your bullet will drift in the direction of the wind. To compensate for this, you must aim into the wind, to the right or left. By aiming right or left into the wind, as the bullet travels downrange, the wind will drift it into the target. Ballistic software websites provide specific wind drift data for your exact load, stated as its "FULL VALUE" that is, for a 9 or 3 o'clock wind. For example, here's the FULL VALUE 10 to 40mph data from my long range rifle 7mm Rem Mag Range Card
Lets use 10 mph data to make an important point you don't need mountains of data and an assortment of windspeeds. 10mph wind @ 100 yards, now look at 400 yards with a 10 mph wind, that's because your bullet is starting slowing at greater range, giving the wind a bit more time to push it off course. The least complicated way to compensate for a crosswind is to relocate. In most situations, repositioning is not an option then you must make your adjustment for windage using a windage knob and clicking in the required right or left compensation, then holding dead on and firing. If this seems confusing, it is at first. But once you get the basics down it becomes more intriguing. Once you start understanding it and put these princables to practice you'll be amazed by the distances you can reach out to. The pic below is my long range with 2 range card 1@ 32 degrees & the other @ 75 degrees with wind meter & compass.
