This is a computer simulation which calculates the behavior of a round ball in its flight from the muzzle to the target. A round ball is unique among projectiles in that its ballistic characteristics are solely dependant upon its diameter (unless it's made of something other than lead). This allows a (relatively) simple physics model calculation to predict how it will behave, once the resistance of a "reference projectile" is known for a range of velocities. The reference, or "retardation" data used in the calculations is based on the British measurements made in about 1908. These relate to the retardation (rearward force) felt by a round-nosed projectile traveling at various velocities. Since a round ball is a (very short) round nosed projectile, I used this data, modified by some real-world experiments, to calculate the effects of wind resistance on the ball flight.
What this program does is to look at all the forces acting on a round ball in flight, such as gravity, cross-winds (if any), and wind resistance. The effects of these forces are calculated for every millisecond (0.001 sec) of flight, giving a relatively exact simulation over the flight of the ball. Note that you do not need to know the ballistic coefficient (BC) for the ball; this is automatically taken care of by the program. Also note that if you enter a caliber, the ball weight is calculated for you, assuming pure lead. This weight may be changed to fit what you actually have. [Note that you should enter the ball diameter you use, not the barrel caliber.]
NOTE!! For those who use Windows 98 or earlier, download this version. Users of newer Windows versions, such as XP, will be better off with this one.
Once you have it, simply run it, and you will be presented with a very inelegant plain screen into which you can type some simple commands. Each command must be followed by a carraige return (Enter key). The commands are:
The output from this program was tested against some real-world chronograph data from my own experiments and also compared against other published tables. The match is fairly close, and I plan to do more tests this Spring to confirm the results. The program will also work fairy well for round-nosed slug projectiles; just adjust the weight after you enter the caliber. At some point I might pretty-up the program with a better user interface, but this one works fairly well, and once you get the hang of it, it is very quick to use. Please email me if you run into a problem.
Hope this helps everybody's shooting!