Despite what most seem to think shotguns are not death rays and DO have to be aimed.
I watched a guy pattern a Benelli M4 at the range one day - I was thinking of buying one and was curious to see what it did. He was using buckshot, and the load made about a 6 inch pattern at 25 yards. Yeah, you have to aim them just as well as a pistol or rifle. I guess some sort of "spreader load" might open the pattern better for short ranges, but then you may not hit the attacker with the whole load.
