Boo.
So, you're not hearing a shooter off in the distance this time; you're face-to-face with a guy with a gun and he's pointing it at you.
Here are some options ...
Stand there and do nothing. Well, I guess you can see if he'll let you scream.
Turn and run. Chances are, if he shoots, he'll miss. If he doesn't miss, chances are he won't hit you in a vital spot. If he does hit a vital spot, chances are still good that you'll survive if you can get away from him and to medical help. Yes, somebody actually did the math: you've got about an 80% chance of surviving.
You may be able to pull this next option off but you have to judge the distance properly, if you decide to give it a try. If you can't reach out and touch his gun as you stand there, don't lunge for it. But you might consider this: Put your hands up like a good victim. Don't scream.
Assuming he's holding the gun in his right hand, slam your left hand/forearm into his right hand/forearm as hard as you can. You want to drive his gun hand toward his left, away from you. His right arm will swing that direction, to his left, more easily than if you slapped it to his right. Plus, to pull off the next step, you need the gun to be moving to his left.
Once the gun hand is moving along that left inward arc, you need to be simultaneously moving past him as quickly as you can, with him on your right. This way he has to stop the movement of his hand, turn around to find you and then acquire you as a target again. If possible. This might give you a couple seconds and may be enough for you to get hookin' and bookin' outa the AO. This move can work with rifles and shotguns, too. Your decision.
If he's got the gun in his left hand, just reverse the move: your right hand/forearm slams into his left; you move off to his left as his arm swings to his right.
But in any scenario, you might not be able to run away. I can't judge that ~ you must. If you have to fight him, at least you got the gun moving away from you. Try to pin his gun arm to his body with your arms a/o body weight.
If you want to get up and go home, you're going to have to be vigorous in your own self-defense. Help might not be on the way.
If slapping the gun to the side isn't possible, you still have an option. This works best when the gun pointed at you is somewhere in the abdomen area and less than an arm's length away from you. This move stays the same regardless of which hand he's got the gun in. Acting as a good victim, move your hands a little so he gets used to seeing them move. Bring them to about the center of your body then hard hard hard and fast fast fast, slam the palm of your left hand up into the butt of the gun he's pointing at you. At the same time, hard hard hard and fast fast fast, slam the palm of your right hand down onto the muzzle of the gun. This should force the rear of the gun up from the grip and down from the muzzle, spinning it out of his hand if you hit him hard and fast enough. You are not trying to grab the gun, you are trying to knock it from his hands. This move works from the side as well though it won't work on rifles and shotguns. Then you can either choose to run away or attempt to subdue the guy.
This is, as always, your choice.
It's not my choice for you.
It is your choice for you then and there.
If the gun doesn't spin out and you're standing there struggling with him, do your best. Bite him, head-butt him, slam him into walls and furniture, but don't let go of the gun. Shout 'Fire' and hope help comes. The question at that time shouldn't be, Gee, I wonder if he'll surrender? The question should be, How bad do I want to go home?
If you even think you might try one of these moves if faced with the threat, you need to get a plastic gun of some sort and practice so you know what it feels and looks like to try this, as opposed to just reading it here.
Remember; these are options for you to consider. No instructor can guarantee that any particular move will work against any particular bad guy or girl at any particular moment in time or spot in this or any other galaxy.
It's entirely your choice to do or not do anything suggested here.
Here's a good Krav Maga move you might try, but be sure to practice it if you think you'll ever need it.

Bite him, head-butt him, slam him into walls and furniture, but don't let go of the gun.
Your advice is always excellent...A long time ago as a younger man, I was hitchhiking across the south with a friend...We got a ride in a panel truck full of plumbing tools, and a drunk or deranged man (maybe both) I was sitting in the middle...The truck ran out of water so we stopped at a rural mom a pop one pump station in the backwoods of Louisiana...My friend got out to put water in...Just then two young maybe 6/8 year old black children, passed by his side of the truck...He snarled 'I'm going to shoot a couple of niggers', he reached under his seat and pulled out a sawed off double barreled shot gun with a pistol handle, pointed it at them, and said, 'come here and get shot niggers'...
Their eyes got big as pancakes...I said 'hey don't do that', and leaned over him grabbed the gun with both hands...As I was trying to pull it inside the window, the barrel lifted up and got stuck above the window, I gave a big pull and it popped inside, but I was falling over sideways to my right...I had to let go with my right hand in order to catch myself, I didn't want him on top of me...But I maintained my hold with my left...Fortunately God caused my right hand to fall on a large wrench...I promptly hit him hard upside his head...He let go of the gun and grabbed his head...
I probably should have taken the gun with me, but I didn't, I broke it open, popped the shells out (it was loaded) threw the gun in the back of the van, and the shells in the bushes, then got out and started running, my friend didn't know about any of this, but when I ran, he ran also...We ran up to the main road and immediately got a ride from the only car in sight...I turned around and looked back, and saw the guy with the gun in his hand looking for the shells in the bushes...But we were long gone...
Posted by: duh_swami | 17 September 2010 at 08:31 AM