For home defense #4 Buckshot. 27 .22 Caliber balls of lead or steel is a poor mans claymore mine. Imagine...27 .22 caliber bullets impacting a hall area all at once. Quickly followed by a second and third trigger pull with the same results. Anyone in that hall is going to be messed up really bad. The #4 allows for a pretty decent spread while maximizing tissue damage. Three shots in quick succession is like shooting 81 .22 calibers guns at a single target at close range. It will get the job done.

A single shotgun slug will also defeat most body armor devoid of trauma plates. And can be shot accurately out to a 100 meters with the same results.

Same gun- different loads for different defense situations.