While the central purpose of external ballistics is to predict where the bullet is gong to land, the other purpose is to explain how bullets fly. Many people on shooting sites have requested simple explanations of how bullets fly, to be told it is way too complicated to explain easily. I beg to differ.
Using four parameters based on the following ideas I end up with 1moa or better description of trajectories. The first idea is that a bullet leaving a muzzle carries energy and momentum. The rate of loss of the momentum is a linear function of the amount of air the bullet has to move. A bullet experiences the force of gravity, but its fall is restricted proportional to the same drag that is slowing the bullet down.
When these ideas are mapped to actual data, they lead to a velocity-distance profile V (S), that is exactly A S^2 + B S + Vz with Vz muzzle velocity, S range, A and B fitted constants. The last constant needed is the ratio of actual drop to free fall drop, using the observed drag implied by the first three constants. For simplicity, I recommend a version of McCoy's drag-drop function, which is (V/Vz)^).3 but you can run the full calculation yourself if you prefer. With the McCoy function most of the time the fall-fly drag ratio is 0.5, so I can usually explain the drop tables with A,B and Vz.
I have tried to summarize the calculations in the site The Analytical Rifleist - Home I would be interested in feedback on what parts do not make sense though it is heavy in math.
Using four parameters based on the following ideas I end up with 1moa or better description of trajectories. The first idea is that a bullet leaving a muzzle carries energy and momentum. The rate of loss of the momentum is a linear function of the amount of air the bullet has to move. A bullet experiences the force of gravity, but its fall is restricted proportional to the same drag that is slowing the bullet down.
When these ideas are mapped to actual data, they lead to a velocity-distance profile V (S), that is exactly A S^2 + B S + Vz with Vz muzzle velocity, S range, A and B fitted constants. The last constant needed is the ratio of actual drop to free fall drop, using the observed drag implied by the first three constants. For simplicity, I recommend a version of McCoy's drag-drop function, which is (V/Vz)^).3 but you can run the full calculation yourself if you prefer. With the McCoy function most of the time the fall-fly drag ratio is 0.5, so I can usually explain the drop tables with A,B and Vz.
I have tried to summarize the calculations in the site The Analytical Rifleist - Home I would be interested in feedback on what parts do not make sense though it is heavy in math.
