The ability to hit a target at (or 10 football fields away) requires the shooter to become an expert in ballistics. First, the shooter has to know exactly how far away target is. They have to be able to compensate for windage (the effects of wind on a bullet). Next, the shooter has to compute the "elevation". This is how far "above" the target the shooter must aim to compensate for the force of gravity on the bullet at a given distance. Shooters have to compensate also for shots uphill or downhill from their position. 