With extended chokes, you can tighten up some, but just running the modified, rule of thumb would typically be that larger shot patterns tighter, until you get past a certain point, then BBs might show blown patterns, while 2s are still a nice pattern. You can’t know, (but only guess) without some pattern work. George Turlock (Trulock) makes excellent tubes, as does Rob Robert’s, Mueller, Briley, and others. You really have to pattern Benelli and Beretta guns to verify POI and patterning vs constriction, as their barrels are notorious for varied specs in bore diameter at the threads from gun to gun. If no time, I’d just load up with #2s through a modified tube, and roll. All the guides provide for geese in Canada was #2s, and a modified steel (IM to full lead) pattern worked just fine.
