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3. Usage

3.1 Configuration Options

3.2 Drag Models

The deceleration of a bullet is calculated using standard drag models. These models were produced by firing a standard projectile at a range of velocities and recording its performance. The ballistic coefficient relates any bullet to the standard model. However, only projectiles shaped exactly the same as the standard will match the model's performance.

For the best accuracy, recalculate the ballistic coefficient of the bullet using your chosen drag model. Most manufacturers report the B.C. using the G1 model, so that is the best to start with.

Available Drag Models

For .22LR use the G1 model. The G1 is good for blunt nose, exposed lead bullets with a velocity less than 1400 ft/s.

3.3 Select Bullet

I have included a datafile of bullets which was taken from PCB by Odd Harvard Skevik. www.stud.ntnu.no/~oddske/ballistikk.html This file will be copied into the share directory.

The first two lines of this file are skipped. For bullet entries, the diameter and description must end at column 40 and are followed by the weight and the ballistic coefficient. Feel free to add additional entries to this file, following the existing format.

3.4 Calculation Parameters

3.5 Trajectory Table Output

3.6 Calculate B.C.

This function calculates the projectile ballistic coefficient based on the input data and the selected drag model.


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