How to use ballistic coefficient (SI units)?

[Gews]

Reading in Russian sources I see they use ballistic coefficients such as these:

BC = 3.0 kg/m^2

or alternatively

BC = 3.0 m^2/kg


That's quite different than the usual G1, G7, etc.

Given a certain muzzle velocity, how do I use that to calculate velocity at some point downrange?

 

[Simon Bridge]

http://en.wikipedia.org/wiki/Ballistic_coefficient
http://en.wikipedia.org/wiki/Trajectory_of_a_projectile

The BC ratings in units of mass per area are just regular ballistic coefficients and not special to Russia or anything. The G-ratings are similar but account for the shape of the bullet. You use them to model the drag in the trajectory relations for whatever model you are using.