Perhaps some NW deer hunters may find this development of interest. The Georgia firm, Trulock Chokes, has introduced a new approach to buckshot with their Boar Blaster choke for 12 gauge shotguns.
It appears to combine an extra-long parallel conical section with 5 parallel steps from bore diameter to a full choke constriction:
It appears to combine an extra-long parallel conical section with 5 parallel steps from bore diameter to a full choke constriction: