However, and forgive me if I did not do a thorough enough job reading this thread, I'm assuming that nobody has ever actually been able to PROVE the bullet path to be anything but directly lineal?
No, it's never been proven/demonstrated. That's what the 'challenge' is about.
It's commonly reported that a shooter/rifle will generate smaller MOA groups at longer ranges; HOWEVER, the true cause has never been discovered. Some people believe the bullets actually fly that way, others believe optics, or statistical chance is the cause. The intent of the shoot thru target is to discover if bullets actually fly that way. So far, based on dozens of groups fired from .224 thru .408 cal, they haven't.
-Bryan
