Where did it go? Next question: As much as I've read about ballistics in recent months it requires digesting before things come together for me. Almost through the last 1/3 of R. McCoy's book the 2nd time... so since Whisper brought up the sonic transition question I'll ask my own: I've read that wind deflection is influenced by the cross section of the shock wave, and from McCoy's book and drag graphs it is plain that drag is lower for a given form as the mach number increases. The only way I can really get my mind around crosswind effects is by vector analysis and in that context high mach=less drag=less drift etc. At what point(relative to the projectile) is the cross section of a shock wave significant? Okay, 2 questions , can anyone explain in lay terms why drag decreases as mach increases?