Two major factors that will get in the way of your perfect shot will be the distance you are from the target, and the wind. The distance will of course make your bullet drop. Luckily you can match the distance at the bottom to the information of your reticule. The same goes for the wind, which affects how the bullet moves horizontally. Again this will be specified on the left of the reticule, and you can match that to the reticule information.