Great suggestion Jeffery Van Zandt. BCs are only accurate at one velocity.....usually listed by bullet manufacturers at the velocity of their optimum BC measurement for Marketing purposes. Using banded velocity BCs....if your ballistic solver accepts them.....adds some measure of improved accuracy. However, the whole concept of BC is comparing subject projectile performance to a standard projectile.....always error inducing. Why not use the Custom Drag Curve developed for the specific projectile and eliminate the comparsion error???