Criminals are cowards. Two things they don't want to happen:
1. They do not want to get shot.
2. They do not want to go to jail.
If you pop off one or two rounds, they are going to be running away so fast, if they didn't get hit.
Most SD shootings are one or two shots, if needed. That's when the thugs realize, oh crap, this guy has a gun and he means business.
A 5 shot 642 is fine for CC.
Also there is no honor among thieves. The ones that can run away will leave their wounded buddies behind. They are not going to stick around to see what happens next.