I think ports tend to catch the wad and or rear wad fins. Found this article below. I love the Trulock choke for the Fed #7 load in my Benelli and am buying another Trulock for my son's Benelli. I know it's not needed, but the 3.5" #7 shell and the Trulock tube will absolutely put a dense deadly pattern out to 50 yards. I have not tested it any farther.

http://www.turkeycountrymagazine.com/12MA/MembersOnly/shootingsavvy.html

Faith and love of others knows no mileage nor bounds. That's simply the way it is.
dogzapper

After the game is over, the king and the pawn go into the same box.
Italian Proverb