When the program starts, this window appears. On the top are all of the variables you can change:
- Muzzle Velocity - The muzzle velocity in feet per second.
- Caliber - The ball caliber in inches (not the bore caliber).
- Ball Weight - The weight of the ball in grains.
- Sight Height - The distance from the top of the front sight to the bore center.
- Sighting Distance - What distance are you sighted in for?
- Crosswind - Cross wind speed in mph (assumes wind at right angle).
- Altitude - Your altitude in feet.
- Temperature - The air temperature in Farenheight.
You will notice that as you enter a caliber, the ball weight is automatically calculated, based on the weight of a sphere of that size made from pure lead. If you want to change the weight, just do it, although the value will change back again if you change the caliber. Also, if you change altitude, the temperature will change to reflect the normal reduction in ambient temperature as you go higher. As with the weight, the temperature can be changed as you wish. Note that all entries have some built-in limits, and if you exceed them you will get an error message in the window.
After you have made your changes, clicking the 'FIRE' button will start the simulation. The results are shown in tabular form in the lower window. If they get jumbled up, just increase the window size a little. The data shown are:
- Yards - the distance from the muzzle.
- Vel - The velocity in fps at that distance.
- Energy - The bullet energy in foot-pounds (fpe) at that distance.
- Drop - The vertical position of the ball, in inches, at that distance.
- Drift - The horizontal drift from a cross wind.
- TOF - Time of flight (how long (in seconds) the bullet is in the air).
Getting hard copy
If you want to print out the results or see them in a spreadsheet, there are a couple of ways to do it. Most web browsers will print the visible contents, but if you want a print-out of all the data, it is easily copied to a word processor or note pad. Simply click in the window containing the data and select the data to be copied; holding the 'ctrl' key and then pressing 'a' will select everything (called a [ctrl]a). You then copy the selection ([ctrl]c) and in an open word processor page, such as the 'Notepad' or 'Wordpad' just paste it in ([ctrl]v).
I have lengthened the reporting intervals so the list is not so long. If anyone thinks the old one was better, please let me know. I have also reduced the minimum caliber so it accommodates down to #12 shot.
More technical information can be found of the main ballistics web page.
Of Interest To Programmers