Ballistics Trajectory Calculator

Input Field Explanations

Drag Function:

This field represents the aerodynamic drag model used for the projectile. The G1 model is a common standard, but there are others like G7 for more streamlined bullets. Users should select the drag function that best matches their bullet's shape. This information is often provided by bullet manufacturers or can be found in ballistics manuals.

Ballistic Coefficient:

The ballistic coefficient (BC) is a measure of a bullet's ability to overcome air resistance in flight. A higher BC indicates the bullet will retain velocity better and be less affected by wind. This value is typically provided by the bullet or ammunition manufacturer and can be found on product packaging or in ballistics data sheets.

Initial Velocity (fps):

This is the speed of the bullet as it leaves the muzzle, measured in feet per second (fps). Users can find this information on ammunition boxes, in reloading manuals, or by using a chronograph to measure it directly. Keep in mind that actual velocities may vary slightly from published data due to factors like barrel length and environmental conditions.

Max Range (yards):

This field sets the maximum distance for which the calculator will compute the trajectory. Users should set this to a value that exceeds their expected shooting distance to ensure they have a complete picture of the bullet's path. Consider factors like the cartridge's effective range and your typical shooting scenarios when choosing this value.

Sight Height (inches):

This is the distance between the center of the bore and the center of the scope or sights, measured in inches. To find this value, measure from the top center of the barrel to the center of the scope tube or the top of iron sights. This measurement is crucial for accurately calculating the bullet's trajectory relative to the line of sight.

Shooting Angle (degrees):

This represents the angle between the horizontal plane and the barrel when aiming, with positive values for uphill shots and negative for downhill. Users can measure this with an inclinometer or smartphone app. For flat ground shooting, this value would be 0 degrees.

Zero Range (yards):

This is the distance at which the bullet's path intersects the line of sight. It's typically the range at which a rifle is sighted in. Users should input their preferred zero distance, which often depends on the cartridge and intended use (e.g., 100 yards for general purpose, 200 yards for long-range shooting).

Step Size (yards):

This determines the interval at which the calculator provides trajectory data. A smaller step size gives more detailed results but may increase calculation time. Choose a step size that balances the level of detail you need with the calculator's performance.

Wind Speed (mph):

Enter the speed of the wind that may affect the bullet's path, measured in miles per hour. This can be measured using a handheld anemometer or estimated based on environmental cues. Remember that wind speeds can vary significantly over long distances.

Wind Angle (degrees):

This is the angle between the wind direction and the line of fire, with 90 degrees representing a direct crosswind. Users can estimate this using a compass or by observing wind indicators in the field. Understanding wind angle is crucial for making accurate windage adjustments.

Bullet Weight (grains):

This is the weight of the bullet measured in grains. This information is typically found on ammunition boxes, bullet packaging, or in reloading manuals. The bullet weight, along with its shape and velocity, significantly affects its trajectory and energy retention.