Some interesting statistics on defense scenarios,
http://thinkinggunfighter.blogspot.com/2012/03/self-defense-findings.html
These are averages, and obviously there can be unusual situations far out of the norm, but:
* Private citizens reload in approximately 0.5% of shooting incidents.
* Overall, shots were fired by the defender in 72% of incidents. The average and median number of shots fired was 2. When more than 2 shots were fired, it generally appeared that the defender’s initial response was to fire until empty.
* Handguns were used in 78% of incidents while long guns were used in 13%; in the balance the type of firearm was not reported. The most common size of handgun was the .35 caliber family (.38, .357, 9mm) at 61%, with most .38s apparently being of the 5 shot variety. Mouseguns (.380s and below) were at 23%, and .40 caliber and up at 15%.
* Multiple conspirators were involved in 36% of the incidents. However, there are no apparent cases of drivers or lookouts acting as reinforcements for the criminal actor(s) once shooting starts. Immediate flight is the most common response for drivers and lookouts at the sound of gunfire.
* The shooting distance in the vast majority of cases was slightly in excess of arm's length. At this distances, even .22s and .25s are highly immediately lethal.
* A revolver, even J-frame, is perfectly capable of dealing with almost all of the incidents. The ones which were beyond the capabilities of a five shot revolver would be best deal with by a shotgun, anyway.
* For those who do not practice, a revolver is far preferable to the autoloader because of the revolver's simpler manual of arms. Eighty per cent of gunshot wounds are self-inflicted. Guns are handled many times more than they are shot and so safe gunhandling qualities are much more important characteristics than its ability to be shot accurately and reloaded quickly. Revolvers are much less likely than autoloaders to AD in the hands of novices.