One question I have is from a post above. Someone was saying that a bullet drops faster in cold weather versus warm weather due to the density of the cold air. Why would the air temperature affect this if gravity is pushing down at a constant?
Air density affects the bullet path independant of gravity. You would need a super computer to try to figure where a bullet would travel in real conditions. You have different air densitys, wind speed, wind directions, bullet rotation speed, bullet velosity and more along the path of a bullet. The only constant is gravity down at 9.8meters per second. So gravity is only one of the many forces acting on the bullets path.
If you can find a vacuum to shoot in. Your bullet will drop 9.8 meters per second directly straight in front of the direction the barrel was pointed when fired.