I hope and pray I nor any of you have to be faced with a deadly force confrontation. That having been said, I tend to belive that a person will revert to what seems the most natural for them should the moment of truth rear its ugly head.
I also beleive from extensive defensive and offensive driving training that the mind and body will respond auotmatically if prior proper conditioning has taken place. That I can tell you from numerous first-hand experiences. In other words the training will become second nature.
I have had a loaded weapon trained on my face at point blank range by a perpetrator with ill intent. Though, I was unarmed at the time, I now have an idea of what to expect should the unfortunate circumstance recur.
My admonition to you would be to first, find the stance most natural to your individual physique that will allow you to effectively manipulate and discharge your weapon in the most accurate and safest manner possible. Then train and re-train so that God-forbid, your reponse will be automatic.
Possibly, practicing on a private range or an open expanse of land with safe and absolute back stops is the only way to prepare for such a circumstance. Most public ranges will not allow such activity. If you can afford it, try a Gunsite or Thunder Ranch setup. Additionally, I would advise you to shoot from inside your personal vehicle, shoot without earplugs and if possible, find an abandoned building or house where there's no danger of hurting bystanders and learn what to expect from your personal weapon of choice when the circumstances are less than perfect. You will damage your hearing posssibly, but you might safe your life or the life of others. Certainly, I would not advise repeated shooting without ear protection.
Also, practice shooting with your head turned away from the target at very close ranges of seven yards or less. In this era of rampant blood-borne pathogens, what would it profit you to buy an expensive deep cover pistol, get you CCL, train extensively and then have the blood of an aids-infected career criminal splattered all over your face after shooting him point blank range to protect yourself or a loved one.
When you get down to it there are so many elements of firearms ownership that most people armed to the teeth don't even consider. Having a solid defensive stance that occurs automatically will help to assure that you are equipped to act decisively should the need surface.
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"When guns are outlawed;I will be an outlaw."