As a Oregon State Police recruit 40 years ago, we practiced every day and every night after class a disarming technique.
Our hands got sore, we got cut,hammers fell on the webs of our hands and we bled, and in the end we learned a skill that would be with us to the end of our days.
Hours upon hours of taking the gun away and handing it back, doing it again, handing it back and doing it again.
Bottom line action is quicker than reaction, it is that simple. Put a gun to my chest cocked and I will take it away from you before you can pull the trigger.
Again, no magic here, it is just that action is quicker than reaction.
So this recruit goes to his assigned station, after a year he gets his Trooper status, goes to a family beef and the offending husband puts a 38 to the Troopers chest. The Trooper reacted by instinct and just like in training, he disarmed the husband like lightening, then handed that gun back to him, just like we practiced.
The shocked husband stood there, revolver hanging limply in his hand, and finally said,"Your F---ing crazy", and dropped the gun to the floor.