After going to Basic Training at Fort Benning, Georgia and qualifying with an M-4 I learned that to be an efficient shooter you have to apply physics. A lot of factors come into play and you can control only so many. Breathing, trigger pull, and steady aim are the general principals. The farther the target the higher you have to aim because the force of gravity will make the bullet drop as it takes flight. In class we learned that a bullet dropped will fall at the same time as a bullet fired because the acceleration due to gravity is 9.81m/s^2. This is a cool new way to look at shooting.