The bc of a test bullet bctest moving at velocity v is a real number and defined as
the deceleration due to drag of a "standard" bullet
the deceleration due to drag of the test bullet.
The standard bullet is said to have a mass of 1 lb (0.4536 kg) and a
diameter of 1 in (25.4 mm). The drag coefficients of the standard bullet
can be derived from the G1-function given in literature
and will be named cDoG1(Ma) .
one finds for the bc (assuming "standard" atmosphere conditions)
bctest=1 / iDtest(B) * mtest / d2test
This formula also shows that the bc and the form factor iD of a "test" bullet are two aspects of the same principal simplification: the substitution of the (unknown) particular drag function of a bullet by the (given) "standard" drag function of the standard bullet (see also here).
||Zero-yaw drag coefficient of test bullet|
||Zero-yaw G1 standard drag coefficient|
||Form factor of test bullet|
||Ballistic coefficient of test bullet|
||Mass of test bullet in lb|
||Diameter of test bullet in inches|