I read as much of the 11 pages as I could (about 4), before I realized I was getting even more confused
I disagree with quite a bit of what was being said, especially the constant denial of a side drift force component on the bullet which follows the laws of physics. I will do my best to explain my position on this.
I am a pilot and I fly my own Cessna 182. When the airplane wheels leave the ground in a cross-wind, and I leave my feet off of the rudder pedals, two things happen:
1. Because the center of pressure of the fuselage and vertical stabilizer and rudder. is behind the center of gravity (big rudder and long fuselage section), the aircraft turns some into the wind. It can't turn more than a few degrees into the wind because the forward motion of the airplane down the runway creates a strong wind relative to the rudder and fuselage which is trying to keep the airplane going straight down the runway. This wind is much stronger than most any cross wind (unless you have a hurricane force cross wind), so the aircraft only crabs a small amount. This turning into the wind on its' own (no pilot action) is not near enough of a crab angle to prevent the aircraft from drifting in the direction of the cross wind. This leads to the second item.
2. Unless the pilot takes action to either lower a wing into the cross wind or put in a lot of rudder into the wind (actually you should do both), the aircraft drifts sideways with the wind. This drift occurs because there is a component of force due to the air molecules striking the side of the airplane. The amount of force is proportional to the velocity squared, the air density and the amount of area exposed to the cross wind molecules.
Because of this, and because the airplane has mass, the airplane is accelerated in drift and follows Newton's second law (f=ma). Because the aircraft is accelerating in drift, its' drift velocity will increase until the force causing the acceleration equals the side drift drag force. The drag force will be determined by the same equation as the drift force, except that a drag coefficient is thrown in as a multiplier. The drag coefficient is very much determined by the shape of the aircraft where the molecules strike the fuselage and rudder sides and attempt to continue on across the top and bottom structures. Needless to say, we are talking a very big drag coefficient here, compared to the drag coefficient which applies to a head on aircraft view.
From this I can only conclude that a bullet in flight experiences the same physical forces and follows the same laws of classical physics as my airplane does. Yes, a bullet does turn a little into the wind (and I mean a little), but it also drifts sideways to the intended flight path (a lot) because of the cross wind force on the side profile of the bullet.
We have no way of knowing what the drag coefficient for this cross wind is for any given bullet, and I propose that it is relatively unrelated to the advertised and/or measured BC of a given bullet. The BC talked about for a given bullet is measured along a straight line to the target and will only change slightly in a cross wind due to the small turn into the wind. The amount a bullet will turn into the wind is much more complex a problem than an airplane because of the spin of the bullet causing gyroscopic effects which counter a turn into the wind, etc.
I believe there does exist for every bullet a BC for drift that is independent of the bullet BC for no wind flight. I don't know what it is and I don't know how to measure it, but I am convinced it exists, and I am also convinced a heavier bullet will drift less in a cross wind than a lighter bullet (given both bullets have the same side area and same drag coefficients for the side area, and given the same time of flight (Newton's 2nd law again). It is easy to make two bullets that meet this criteria by just using different density materials. From this a “drift BC” could be applied to the bullets just like a regular BC is applied to forward motion, and it would give us a true measure of how well the bullet bucks the wind.
For now, it is agreed by most everyone that a higher BC bullet has less wind drift than a lower BC bullet, given the same time of flight. What is not even close to being agreed upon is exactly why that is true. But don’t tell me the cross wind doesn’t exert a force on the side of the bullet, or that the bullet doesn’t drift, but turns into the wind!