The situation you describe , Rich , makes for the extreme measure to go for the gun rather than to be passive and die without a fight ! You may still die when charging the gun , but you may buy a few precious moments for your wife /children to get away , if they don't freeze in their tracks first , which is very possible !
Here is what the general view of the experts is when mindsetting to go against a gun ,unarmed, in a desperate effort to save your life:
1] First , [ Even if you dislike guns] you must familiarize yourself with what a gun feels like in your hands and the dynamics of it's function before you can visualize ways to neutralize the hand hold of the assailant !
2] Understand the mind set of the man with the gun ! He is usually a coward who really believes the gun makes him invincible and is very confident of his intimidation factor , thereby getting complacent and not even thinking of a surprise unarmed counterattack !
3] Most people shot by a handgun do not die [less than 10% do] ; if you charge the gun , you may only be hit once, as opposed to five or more times if you stand still or retreat ! The more the hits , the more the chances of dying !
4] Once your adrenaline flows , you will not feel much pain initially from a shot , and you can continue moving unless hit in the spinal cord or the brain !
5] The rule of thumb when fighting a man with a weapon [ club, knife, gun etc.] , is to disable the man holding the weapon and not initially going for a disarm technique ! This means you must first concentrate on deflecting or isolating the weapon away from your target areas ; next fight him to disable ; then take away the weapon !
[ Our bunkais are not performed properly by lots of us who insist in throwing counters , such as elbow strikes, without first isolating or controlling the "weapon" arm , thinking their elbow counter is their technique of doom ] !
6] If you are facing the gun on the street , it will probably be from five to one foot away , if the criminal is bent on shooting you in the head , giving you some chance at a sudden surprise rush !
7] The hardest part here is to make yourself do something under the gun ! You must mindset well in advance , over and over , to propel yourself into the weapon in a split second as soon as you perceive the danger ….any hesitation will kill you for sure ! Most of us will freeze anyway , regardless of mindsetting !!
8] One suggested approach , as you careen into your assailant , is to visualize an imaginary straight line of fire between the gun and your body/head , and to curve into him around that line ! As you close the distance , remember that any fancy bunkai technique you think you know , will deteriorate quickly if it relies on fine motor moves ! It is recommended that you charge with a double shuto and forearms into the wrist / hand /arm holding the weapon following through for maximum deflection/isolation by grasping the arm and holding it out of harms way , while you try to stun with knee strikes , elbows / take downs etc. Then take the weapon away !
This is where the head butt is king ! A vicious debilitating technique for some of you who wish to embrace it's practice !! Also think of 'biting' chunks off his face to get his mind off the gun he is holding ! And when that close , don't be adverse to sticking a finger in his eyes ! Rip out the throat ..remember this life or death ..if he gets that gun back on target , you are done for at that range ! You must turn into a vicious animal to prevail physically and mentally over the gun wielding punk !
9] Expect the gun to go off with deafening noise , blinding flash and hot powder gases which may well blind you if the shot is close to your eyes ! That is another reason why you should know what a gun feels and sounds like before you even think of going against one !
10] If you succeed in stopping the threat and you take the weapon away , you will have to secure the gun , handle it safely before it goes off in your hands under stress and or hold it in such a way that it is not a threat to bystanders or responding police ! If police arrive drop the gun ..throw it away from you and the assailant !
All very complex and demanding ….most of us will not be able to handle the charging of the gun ..will go into denial …and into a freshly dug grave !