"The drag vector on the individual pellets.

Once the drag force on the shot mass leading edge slows the leading pellets the trailing pellets push them out of the way to all sides and this starts the dispersion.

Once it starts, it's accelerated by the drag vector on each pellet.

The more out of plane it gets, the more side force."

So is it correct to assume that if we were able to mark individual pellets, we would find that those on top were on the outer edges of the pattern and those on the bottom were in the core of the pattern?