The performance specifications used to describe most shooting equipment is easy to grasp. With rifles, we have trigger weight and length of pull. On scopes, we talk about magnification and objective lens size. Bullets are bit trickier, however. The common performance attribute for projectiles—ballistic coefficient (BC)—is more difficult to understand. Here’s what it is and how it is measured.
Ballistic coefficient is the number used to determine how well a bullet flies; in particular, how well a bullet will retain velocity.
Retained velocity may not seem as important as drop, or wind drift, or kinetic energy (KE). However, retained velocity fundamentally affects every aspect of external ballistic performance. A high BC bullet retains velocity well and will have less drop and wind deflection, and it delivers more KE to a distant target. Understanding BC is critical for any type of long-range shooting.