The expert on the 2 3/4 shells was in the book called the Art and Science of Shotgunning. It is an amazing book in terms of discussion of loads and patterns. I have tried it out and stick with the low brass shells and 1 oz of shot. Gets the best pattern out of my Berratta 391. I get blown patterns when I go with the 3" heavy game loads. Take a shot at some plywood and see what works for your gun. Some of the larger bore guns like the Mossbergs and Remingtons actually perform ok wth the heavy loads. Berratta and Benelli are tighter barrels at the choke and need the lighter loads to pattern well.