Late to the party, but am passing along the following reminder. Shot passage/flow through the forcing cone constriction, as with the choke constriction, is an orderly process, not some slam, bam chaos. The leading shot pellets speed up to get out of the way of the following pellets. Since there is no extra energy input available, the velocity increase must come at the expense of pressure. That is, the pressure drops across the forcing cone constriction and across the choke constriction. I know this is counter-intuitive, but it is so. If not, airplanes don't fly.

Post back if you desire further discussion.

DDA