BC stands for "Ballistic Coefficient". In words, BC is a measure of how well a bullet retains velocity; the higher the BC, the more velocity is retained, and vise-versa. Heavy bullets with streamlined profiles will have higher BC's than shorter bullets with blunter profiles. BC is the fundamental measure of external ballistic efficiency and performance. The higher the BC, the better the bullet retains velocity/energy and resists wind deflection and drop.
BC is more important for long range shooting than short range. The BC’s of Berger bullets are based on carefully controlled test firing and are accurate to within +/- 1%*. All BC’s reported for Berger bullets are corrected to the ICAO Atmosphere.
*For some flat based bullets which are typically used at short range, BC’s are based on calculated rather than fired BC’s.
How do I use BC?
The Ballistic Coefficient (BC) is used to do external ballistic analysis. The most common use is to input the BC into a ballistic computer program along with other data about the shooting conditions (muzzle velocity, zero range, atmospheric conditions, etc) in order to calculate a trajectory for the bullet. The trajectory information is used to make sight corrections for drop and wind deflection. BC's of various bullets are often compared when selecting a bullet for a particular application where external ballistic performance is important. One example is long range target shooting where the shooter wants a high BC in order to minimize wind deflection. A high BC does not indicate a more accurate bullet. However, a high BC does minimize the effects of many shooting variables like uncertainties in range and wind conditions. Thru minimizing the effects of the uncertainties, the higher BC can reduce the net miss distance compared to a bullet with a lower BC.