Played with my SBE yesterday, and wanted to see what the difference was between 3" and 3.5" Fed HW #7's.
40 yards 10" circle
3" 150
3.5" 202
50 yards 10" circle
3" 82
3.5" 118
3.5" gets the nod on these. That said, a turkey target with both 3" and 3.5" shells indicated lethal hits regardless of the shell at 50 yards.
Just found this great site!