Bullet Paramaters

Determining and Defining Bullet Parameters

When entering a new record, the Bullet Length and In-Case fields are required fields for the calculations and must be entered as the last two entries in the 12 entries of the sequence.

After the Bullet Length Field value has been entered and the field is exited, if the In-Case field is blank, the bullet in-case length will be automatically calculated as approximately 50% of the bullet length. You must first exit the In-Case field before that value may be edited.

When the In-Case field is exited while entering values for a New Record, all remaining values will be automatically calculated.

After the remaining values are calculated, the In-Case field may be edited to any reasonable value without causing an error.

The Twist Rate and Muzzle Velocity field value entries are optional. They may be used to calculate an optimum bullet length that is appropriate for the caliber and useful muzzle velocity of the application.

When entering the twist rate, enter only the value that signifies the distance of the twist rate. If the value is 1 turn in 16 inches, then enter the value 16. Do not enter a value such as "1/16" or "1 in 16".

If the bullet length and the muzzle velocity are known, then enter those values and click the button to calculate the twist rate.

This formula will be used to make the calculation: T = ( 3.5 * SqRt( V ) * D² ) ÷ L

If the barrel twist rate and the bullet length are known then enter those values and click the button to calculate the muzzle velocity.

This formula will be used to make the calculation: V = ( L * T ÷ D² ÷ 3.5 )²

If the barrel twist rate and the muzzle velocity are known then enter those values and click the button to calculate the bullet length.

This formula will be used to make the calculation: L = ( 3.5 * SqRt( V ) * D² ) ÷ T

The formulas are modifications of the Greenhill equation that consider the muzzle velocity of the bullet.