Personal observations:
The Ithaca chokes I have measured have little to no parallel, and as a group have generated the better patterns. Period.
The shortest chokes I have measured (0.75-1.0" taper) were the work of a highly rated aftermarket supplier. As a group they have produced the poorest patterns.
Reclaimed shot. When I reload new shot, some of it always ends up on the bench, rolling every which way. Stray reclaimed shot hits the bench and stays put - doesn't go anywhere. The takeaway is that the deformation didn't happen when the shot hit the ground, or when it left the barrel, but rather in the barrel. It left the barrel deformed, every piece guaranteed to have at least one flat spot.
