BALLISTIC COEFFICIENTS and the ballistic calculators that rely on them to compute bullet trajectories have been a mainstay for shooters for years. But as anyone who’s dealt much with BCs knows, they are messy things.
First off, BCs—which, roughly speaking, measure how well a projectile handles air resistance—aren’t constants. The actual value of the BC of a bullet in flight changes depending on how fast the bullet is traveling. Put another way , BC varies with distance from the shooter. So when you see a published BC, you have to wonder at what distance, and under what environmental conditions, it was calculated.
Secondly, BCs are grouped based on projectile shape, the most common categories being G1, for typical pointed hunting bullets, and G7, for sleek VLD (very low drag) bullets.…