Im thinking I might need some explanation on this chart.
The chart isn't very intuitive, but I believe I have an explanation for you. For the chart for a given target (e.g. M18), when looking at the vehicle through the sight, find the row showing the approximate number of mils that the target covers, then go the appropriate column as to whether that is the width (e.g. you are looking at it head on, and you are therefore seeing the width of the vehicle in your sights), length, or height of the vehicle. The number there is the approximate distance to the target. For instance, if you are looking at an M18 side on, and it covers 2 mils from end to end, then the distance would be 2890 yds, because 2890 is the number under the length column for 2 mils.
Mike