Ballistic Coefficient (Velocity) Terms

Input Data

Altitude
Used in estimating the atmospheric conditions. This value is not used unless the "Standard Conditions at Altitude" checkbox or the "Pressure is Corrected" checkbox is checked.
Chronograph Separation
The distance from the point of the first velocity measurement to the point of the second measurement. This is the distance between the two chronographs.
Drag function
A drag function (or G function) provides the forces on a standard bullet for which the drag function was derived. A bullet's ballistic coefficient then relates the drag on any bullet to that of the standard bullet.
Far Velocity
The velocity of the bullet at the end of the measured distance.
Near Velocity
The velocity of the bullet at the beginning of the measured distance.
Pressure
The barometric pressure. It may be corrected or uncorrected depending on the state of the "Pressure is Corrected" checkbox.
Pressure is Corrected
Check this box if the pressure entered is a corrected station pressure. If it is an absolute pressure, leave this unchecked.
Relative Humidity
Relative humidity (percent)
Standard Conditions at Altitude
When checked, the temperature, pressure and humidity for standard atmospheric conditions at the entered altitude (always 0% at standard conditions) are entered in the calculation. The standard used is the ICAO standard atmosphere.
Temperature
The measured or estimated air temperature.

Output Data

Ballistic Coefficient
The calculated ballistic coefficient for the selected drag function.
Atmospheric Density
The calculated density of the air.
Speed of Sound
The calculated speed of sound.
Time
The calculated time of flight of the bullet over the entered distance.

Note: If a ballistic coefficient cannot be found with the input values, the text "***" will be displayed for the ballistic coefficient and time of flight.