I've seen a table showing maximum distances various shot sizes will travel, but I'm not sure now where I saw it. Could have been in the back of an old Dixie Gun Works catalog, but I'm not sure (don't have a copy on hand).
If I remember correctly #8 shot would only fly about 225 yards, with larger sizes traveling longer distances (dramatically further as the size increased).
This has nothing to do with EFFECTIVE distance, just MAXIMUM distance.
A rather unscientific experiment that may give you some perspective is to throw a common BB as far as you can and then throw a golf ball as far as you can. Starting velocity (arm speed) will be about the same, but you'll see a tremendous difference in the distance they travel!