The instant the gun is off them, they’re going to neutralize their opponent. That doesn’t necessarily mean kill, but it could easily. A couple of gun disarms I know end in executing the original owner.
I’m just going to use second person construction here, because otherwise this will be a really unwieldy post, but: do not do this at home. I’ve said before that gun disarms will get you killed, and I mean it. Trained martial artists, who think they know what they’re doing and have trained for years get killed or seriously injured trying to pull these off in the field. From what I know, the survival rates for cops and special forces types who actually try to do this stuff aren’t much better. The real world application for this stuff is in the range of, “well, they’re going to kill me anyway, might as well roll the dice for a slim chance of survival over the certainty of death.”
Okay, with that out of the way:
So far as I know, almost all gun disarms work off a basic structure. Get the gun’s fire arc off of you. Make sure the assailant can’t get it back on you. Neutralize the assailant or their weapon.
The first step can start the instant the gun comes out. Usually the best time to go is whenever the gun wielder gets distracted, or manufacturing a distraction to get their attention off their target. Consistently, this is also the most dangerous, because if you misjudge someone’s distraction you will get shot for trying something.
Getting the gun’s arc of fire off of you can be as simple as stepping out of the way, but it always needs to be followed with something that makes sure the attacker can’t simply redirect the gun back on you. The easiest way is usually to close the distance so you are too close to actually shoot, while tying up the gun arm. This is consistently the most dangerous part for other people. Because the gun is pointing somewhere the shooter didn’t intend, and because they’re startled, there’s a pretty decent chance they’ll put a couple rounds in the general vicinity of someplace they weren’t aiming.
Thing is, the second step is just a delaying tactic. It won’t last long. So, then you need to move into the third step and deal with either the attacker or their weapon. That you must either get the weapon away from them, or kill them. There are a few ways to do this. Some stress positions will allow you to simply slip the weapon out of the shooter’s grasp. There are close quarters pistol positions that can be employed when you’re inches away from the target. It’s messy, but pumping three rounds into someone’s gut usually will usually keep them distracted from trying to shoot you.
If they’re behind you, that means you need to be facing them as quickly as possible, usually both getting the weapon off of you and making sure they can’t simply adjust their aim at the same time. From hands up in a defensive posture, you can do all three in a single motion.
Here’s a few of the ways it can go horrible wrong:
First are shooters that partially draw before firing. This technique primarily comes out of rifle marksmanship, though it applies to all firearms.
The way this works is: With any firearm, the trigger has a break point. This is the exact place in the draw where the mechanism releases the hammer and the weapon goes off. This is different for every gun. Not every gun model, ever individual gun is slightly different in this regard.
When you’re drawing the trigger the weapon will move slightly. It doesn’t matter if it’s a hunting rifle or a SIG P220, you’ll have some barrel movement. This is a function of how your hand is put together, and exerting a couple pounds of force with one finger. But, you can mostly draw the trigger and then adjust your aim.
If you started training on a rifle, which, honestly is a lot of people, and you’re familiar with your handgun, this behavior is very natural. To the point that I don’t honestly think about it that much, but it will completely screw over anyone who tries to grab your weapon, because the amount of force needed (and the time necessary) to get a shot off will be much lower than with someone who doesn’t know their weapon, or know how to shoot. They flinch, you take a bullet.
(Incidentally, a hair trigger is one where the break is very close to the trigger’s resting position, meaning the shooter doesn’t have to tense against it at all.)
Getting the gun’s arc off of you is a “better you than me” tactic. With a few exceptions, the shooter will still have the ability to fire their weapon, they just won’t be able to use it on you. That means anyone in the general vicinity is at risk of taking a bullet, or bullets. While it is possible to avoid getting shot it’s almost impossible to prevent the shooter from getting a shot off.
There are a few techniques where this isn’t the case, but they’re mostly highly situational (or, in the case of one Marine technique, hilariously dangerous).
Basically, if you’re trying to execute a disarm, you’ve decided that everyone around you is expendable in your quest to keep living. The chances someone will actually get shot are fairly slim, but you cannot protect them. That is to say, if you thought about having your character who works as a bodyguard do this, stop. It will end with them out of a job.
Now, the smartest way to deal with someone who has a gun is to make sure they don’t have a chance to draw it in the first place. I’ve seen it alternately defined as the 8ft, 2m or 10ft rule, where unless you’ve specifically trained to draw quickly in tight quarters, you can’t get a gun out and ready to fire before someone at that distance can close and attack. But this is dealing with Someone who has a gun preemptively before they’ve drawn it, not dealing with someone who’s already got one out.