Ballistics
The drop values for your table are based on a theoretical drop. This drop is a function of gravity, the muzzle velocity, and how fast your bullet slows down (deceleration), and the drag function that your software uses.
The deceleration is a function of the physics of your bullet (ballistic coefficient) and atmospheric conditions, (temperature, humidity, amount headwind, tail wind, and your elevation (air is less dense the higher up you are)). The ballistic coefficient is a theoretical unit calculated from the shape of your bullet, and can be altered by the properties of your chamber, and barrel. The bullet that leaves your barrel is not the same one that went in the chamber.
All this means is that the numbers you get from your program will only be guides, you will need to finalize your drops in the real world, and keep in mind that at long distances these real world drop values can vary from session to session, as the conditions under which you are shooting will not always be the same.
I use a .308, with Berger 175gn vld’s carefully prepared brass, match primers, and accurate powder measures. I have measured my loads over a chrony many times , and have very tight standard deviations for the measured velocities. I have even fired these loads over a chrony at 100 and 200 yards to compare the changes in velocity and calculate the true ballistic coefficient for this bullet in my rifle. Using all this data, and a custom drag function I still find that my calculated MOA come up at 1000 yards is about 3-4 minutes less than the actual value I get at the range.
For short distances (< 300 yards) the calculated values may be close, but the farther you shoot, the more you will have to rely on your field values.
