HoJutsu is the samurai term for marksmenship/gunnery techniques. Every Jujitsu school should teach gun disarmament and marksmenship, if they don't they don't have the entire curiculum so to speak.
Even if a gun is touching you, you have the same chance of disarmament as if it were at arms length. The distances involved are insignificant to the speed of the bullet. The technique changes alittle is all.
As far as the realism of disarming someone with a gun, it goes like this:
Has everyone played that kids game were two kids hold out their hands, palms facing each other, and the one with their hands on the bottom tries to slap the others hands, while the other tries to react and move their hands out of the way when they see the other person's hands move? Some sort of weird pattycake slap game. Anyway, this is a perfect example of gun disarmament. In the game, usually about 70 to 80% of the time the person trying to slap makes contact. With the gun its the same, only you have a greater advantage because not many gunman are even thinking that you will resist. Who ever reacts first will win. Moving your hands out to intercept the gun can be faster then the gunman's squese on the trigger, because you acted first.
My school has a basic gundisarmament technique, the first thing ever taught about guns. And one of our students tryed it out with paint guns, he told the shooter to fire when they saw his hands move. Out of 10 tries he got hit only once in the shoulder. Granted the paintballs are much slower then bullets, but then again the shooter was waiting for him to move as well.
