Maximum Distance 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.
Ballistic Coefficient
The ballistic coefficient for the bullet being used. It is almost always obtained from the manufacturer, but can also be measured. The ballistic coefficient is represents the ratio of the drag of the standard (e.g. G1 standard bullet) bullet to that of the bullet you are shooting. A ballistic coefficient of 0.100 means that your bullet has 10 times the drag of the standard bullet.
Bullet Library
A drop down list showing all the buttons in the library. If a bullet is selected, the trajectory is run with the selected bullet. If "None" is selected, the entered BC, drag function and bullet weight are used. Lapua bullets with "(CD)" in the description use the Drag Coefficients supplied by Lapua instead of the ballistic coefficient. Bullets with "(Litz)" in the description use Bryan Litz' BCs.
Bullet Weight
The weight of the bullet
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.
Muzzle Velocity
The velocity of the bullet as either (1) measured at some distance from the muzzle or (2) as estimated from reloading data.
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

Maximum Distance
Maximum distance achieved.
Initial Angle
The angle of the barrel relative to the ground.
Terminal Range
The distance achieved by the bullet for the elevation.
Maximum Height
The maximum height above the ground that the bullet achieved, in feet.
Terminal Angle
The angle at which the bullet strikes the ground. Ninety degrees is straight down.
Terminal Velocity
The final speed of the bullet in feet per second
Terminal Energy
Really the "Kinetic Energy" of the bullet. The kinetic energy is a measure of the maximum amount of work (force time distance) an object can do. [It is also a measure of the work done by the firearm/case/primer/powder on the bullet.]
Time of flight
The time of flight of bullet in seconds.