That's all covered in the thread I referred you to. I go to some length to describe why that's not the point. I see no reason to repeat all that here.
Originally Posted by absynthe49
But one thing I will comment on. Whenever someone comes up with a hypothetical to support an argument as to why this isn't an issue, he seems to tells a nice, clean, simple "good shoot" story. Unfortunately, things aren't always that neat. Real life can be messy, and if you're on trial in the first place, the DA or grand jury didn't think it was "good shoot." So try this one on for size.
A guy in a parking lot 7 yards away from you is looking at you and making threatening gestures in your direction with a large butcher knife he's holding in his right hand. He shouts that he wants your money. You're holding your gun drawn in low ready and order him to drop the knife and go away.
At your trial for manslaughter you testify as to that and then say that in response to your order, he begins to raise the knife and move toward you. You further testify that you were in fear of your life, you could not effectively retreat because your back was to a group of closely parked cars, so you believed that you had no choice but to shoot. You shot several times, and he crumbled, dropping the knife as he fell. He never moved again and was dead when the EMTs arrived
However, an eyewitness testifies that the alleged assailant had actually broken off the attack before you fired. He had dropped the knife and started to turn away, and only then did you shoot.
And the forensic pathologist testifies that, based on the entrance wounds and position of the body, he was turning away toward his left when he was shot. Also, given the nature of the wounds, he would have most likely have retained his grip on the knife when he was shot, although it's not impossible that he would have dropped it.
Now your lawyer has to explain or overcome the eyewitness and the forensic pathologist to solidify your claim of self defense. It's also very useful to your case for the jury to believe your account of what happened and the way you perceived things. Do you think that whether members of the jury see you as a solid, responsible citizen or as a gun nut who irresponsibly tampers with a safety device that the maker of the gun thought was important enough to incorporate to make the gun safer to handle would make any difference in how they evaluated your testimony? Do you really want your lawyer, in addition to having to deal with the testimony of the eyewitness and the pathologist, to also have to try to explain to the jury why it was reasonable and not irresponsible of you to remove the safety device?
In general, the less you have to explain, the better off you are.
adapt, improvise, overcome
"Extraordinary claims require extraordinary evidence.", Carl Sagan
"One should shoot as quickly as one can -- but no quicker.", Jeff Cooper