@lks @WilhelmIII @Evil_Bender @BattleDwarfGimli @JohnSmith87298753 @lovelymiss @brokeassredneck This right here. One instructor at a defensive pistol class I took called it the rule of 3's. Most gunfight encounters have these three characteristics:

3 yards or less.
3 rounds fired.
3 seconds duration.