Suggested reading......
Massad Ayoob
In the Gravest Extreme
Stressfire
Both books are excellent. The first speaks of the use of deadly force and IMHO should be MANDATORY for anyone before they get the gun. What should you be thinking about before you even buy a gun.....deadly force, legality, type of gun...for example...He makes reference to a homeowner using an SKS to defend his home....(let me say now that I believe that if you are to the point of using lethal force, then it doesn't matter to me what you use to deliver it, but....) he points out that if you are brought up on charges, it doesn't look good IN THE COURT to the JURY that you used "An assualt weapon". And as he said...the lawyer will definitely bring up that point!
The second speaks of what to expect (physiologically) during and after a gunfight. For example...ever notice how after a car crash the drivers begin to just start 'rambling' on about how "this" happened and how "that" happened....it is referred to as diarrhea of the mouth.....and you can expect it after the shooting too.....so learn to keep your mouth SHUT.