I used to shoot IPSC stock class, I can personally support this.
Coached, skilled, and well drilled handgun shooters can put center mass shots on moving targets at 15-20 yards, but put any stress, even the time pressure of a timed shooting match stage, and they will be lucky to put 1 out of 3 in the target at all.
We used several types of moving and pivoting targets, it takes some decent skills to consistently hit under these conditions.
To the people who explained how a gun works: thanks, that was the info I suspected and wanted. Like I said, I think it was bad advice.
To the person who said you either evade or fight: Sorry, not true.
To the person who wondered why a mugger would get close to you: Have you ever been mugged? They want your money, not a conversation. Plus, they don’t want you far enough away to have a simple escape. :smack:
Yes, on some autos there is a hammer. Others use a striker. Now, the way they work is that the barrel, chamber, and slide are all kept together. The hammer and sear (the part that holds the hammer back. is part of the frame. Since a round has to be in the chamber before firing, removing the slide disables the gun. If you remove the slide, you also remove the barrel and chamber, no way around it, so an auto without a slide is does not function.
Now there are different types of autos that have the barrel mounted to the frame, but still, without the slide, the gun is a paperweight.
Watch out if it’s a Glock semi like mine. There is NO manual safety for you to grab and normal procedure is to keep a shell in the chamber. But one could stop it from firing by pushing back wards on the slide. I would hate to depend on that but it would be worth a try if the person is planning to shoot you.
Also someone mention about revolvers… they said to put your finger under the hammer. Well… my wife’s Lady Smith revolver is hammerless!
But again it can be disabled from firing by holding the cylinder. Sure have to be quick… for all she has to do is pull the trigger.
RevCo
As someone else already pointed out. The fastest a bullet is ever going to travel is going to be as soon as it leaves the barrel. Plus, if you hold the gun as close as possible, the escaping gasses behind the bullet can blow the skin off of you around the bullet hole. Nasty nasty.
You better find some science to back up your assumptions before posting. 
I think people are putting too much emphasis on the idea that you’re going be able to somehow interfere with the handgun’s mechanism.
What I’ve seen demonstrated and taught is simply the ability to push the gun aside extremely quickly (i.e. make it no longer point at you) and then disable the gunman by punching, kicking, stabbing or shooting him (with your own weapon) before he as any time to react. With a decent amount of practice I’ve seen this work everytime (in simulated senarios of course).
However this is not something that gets taught at a self-defense class at the Y. This was part of a week-long paramilitary seminar for serious hand gun training (it was open to the public but many attending were poilce officers).
As one of the posts above said, the best defense against a hand gun wielding criminal is to run away. Hitting a moving target with a pistol is much more difficult than it seems.
[QUOTE=engineer_comp_geek]
I’ve read that the best defense against someone pointing a pistol at you is to just run. Most people aren’t all that accurate with a pistol, especially in a high stress situation. Even someone who goes to a target range isn’t going to be used to shooting at a live moving target (usually). You might get shot, you might not, but even if you do, most likely it won’t be a fatal wound. There’s still a chance you could die, but the odds are in your favor.
QUOTE]I have to agree. Also, if you are running away you don’t present a threat to the person with the gun and they may not shoot.
You may be able to grab a gun and keep it from firing by jacking the slide (if it’s a semi-auto. In a wrestling situation, that won’t last long). Talk, distract and run like hell.
If I HAD to try to disarm someone with a gun, and if they were stupid enough to let me get close enough, I would try to grab the gun hand WRIST with both my hands and all my weight. And hang on for dear life. The shooter will only have his weak arm to try to beat you away, and you may have the ability to wrench the shooters wrist, or elbow to make him drop the weapon.
If the guy has a Beretta M9/92/96 or a 1911 Government-model .45, you can grab the guy’s wrist with one hand and push directly on the end of the barrel with the other, it’ll push the barrel and slide back a quarter of an inch. There’s a disconnect mechanism that prevents the gun from firing when the mechanism isn’t fully locked up (to prevent it from going full-auto), and pushing on the end of the barrel takes it out of battery enough for the disconnector to engage.
That only works on guns with recoiling barrels, though – if you try it on a blowback-operated gun, you’ll end up with a very large hole in your hand. For those you’d have to grab the slide, which is a bit more difficult.
Of course, now you’re standing there holding hands and you can’t let go or you’ll get shot. Best to have a friend with a large blunt object sneak up and wallop the gunman at this point.
The Space Shuttle is a rocket, and guns don’t fire rockets.
There used to be a rocket pistol in production called a Gyrojet, and the ammo did indeed need some time and space to get going, about 25 feet if memory serves. If you were ever threatened by a Gyrojet your tactic would work, otherwise it’s a very bad plan.
Also on revolvers and some autos if you can get a finger in the space behind the trigger, it can’t be fully depressed and will not fire. You might get a hurt finger, but its better than being shot…
Trying to do something as intricate and specific as getting a finger or part of a hand on or into a particular place on the weapon is extremely difficult to accomplish. The broader the move, the more likely it is to succeed. Even trying to grab the attacker’s hand/wrist is iffy, but if you’re compelled to do something with your hand it is the far better choice over trying to manipulate the gun itself. Better yet is what Hail Ants described.
Well, that depends, have you ever had your finger hurt?
The DVD I saw (from the Krav Maga folks that are a little bit sloppy) had you move to side, grab top of gun (not rely on stopping it from firing), punch or kick, then use 2nd hand to grab bottom of gun and twist both towards the thumb about 90 degrees, the idea being that it’s easiest to pull the gun off the finger that way.
The running idea is good, but if you had to deflect the gun and get a few punches or eye to finger (!!!) in there before running thats good.
Anyway, topic is over. Thanks for all the info.
When Lee Harvey Oswald was caught in the theater after shooting Kennedy, he pulled a revolver on Officer McDonald. He tried to shoot, but McDonald got his finger stuck under the hammer, and the pistol wouldn’t fire.
Which is just more evidence that the whole thing was a government conspiracy, because I don’t think there were any ninjas serving on the Dallas PD at that time. 
Assuming that I had the skill to do either (an assumption which I do not make), I would much prefer getting the gun pointed away from me over temporarily preventing it from firing. As long as it’s not pointing at me, I want that gun to fire. Every time the gun fires, that’s one less bullet that might eventually end up in me, and the gunfire is likely to attract attention, which I probably want (but which the gunman doesn’t).
Again folks, no body said try to stop the gun from firing over getting it to stop. :smack:
Huh? Color me confused. This from the OP (all bolding mine):
…if you grab a revolver or semi-automatic pistol correctly you can prevent it from firing.
Seems to directly contradict these:
*The DVD I saw had you move to side, grab top of gun (not rely on stopping it from firing)…
…no body said try to stop the gun from firing…
The whole OP is asking about the feasibility of stopping the gun from firing, and suddenly now it’s not? 
The guy was about six feet from me, and I was taken by suprise. I immediately grabbed the pistol in both hands and pushed it sideways so it wasn’t pointing at me. We struggled for what seemed like a long time although I suppose it was only a few seconds. The gun was pointed up over my head when I fell backwards and he fell partially on top of me. Somehow, although the gun was in his right hand, it was now over my right shoulder. It fired harmlessly into the ground. Then somehow - I’m not sure how - I manged to get the gun out of his grip, jump up and run.
I’ve been around guns a lot, but this was the first time I’ve been on the wrong end of one. I’m pleased that I handled it well, without hesitating at all.
Would I recommend this to others? At such a short distance, yes. Farther away, it would depend on how fast you can run and whether there’s any cover. Remember, concealment is usually not cover!
I faintly remember a show about crimes that had an officer get into a struggle with a gun touting robber and end up getting a finger cut from the hammer hitting his hand. Seems possible to me. When you’re fighting for the gun and you’re starting to lose, it might make sense to disable the gun and put your attention into hitting the shooter.
But as others have said, shooting someone while excited or nervous is hard. I can shoot my paint marker really well on a range but get me running 2 miles in the woods with a bunch of other excited people and it usually takes me a dozen shots per tag.