My evolving thoughts are that a man would have to stay ahead of the curve when it comes to the use of violence to promote justice in a scenario with no law enforcement.
For example in a situation where a man says "Give me your back pack or I will kill you," you need to believe him and put 2 in the chest and one in the head.
The option is that while some guys would just be barking, many will be unleashed from the rule of law and ready to bite. If you do not take the lead you will end up dead, it's a numbers game. Again, this is only in a no rule of law, complete societal meltdown, your on your own scenario.
"Both oligarch and tyrant mistrust the people, and therefore deprive them of arms." - Aristotle,