When training to fight off a disarming attack, you need to take into account the following factors: it's usually a surprise attack, you and your attacker will be moving, you will need to deliver counter strikes to not only cause pain but also true dysfunction, and you will have to follow up once there is an apparent separation from the attacker and your gun. Your training should focus on both general fighting skills and weapons retention/disarming tactics.
Phil Messina, training consultant and retired New York City police officer, says the fight is not about your gun, it's about the individual who is trying to take your gun.
"From a tactical standpoint the biggest mistake seems to be that the officer tries to turn it into a contest over a gun, rather than a fight with a person who happens to be trying to take [his or her] gun," Messina says. "In the real world, it is likely that you will have to literally disable that person (at least temporarily) before you can realistically have sole control of your own gun. The officer often moves away, turning the fight into a tug of war, which usually goes to the stronger or bigger person, rather than moving in and winning the fight. Moving inward gives you multiple opportunities to retain your weapon, while moving away usually only gives you one."
Messina offers this advice to trainers: "Trainers have officers spend too much time practicing by sight and not enough time practicing blindfolded. Often the first indication that someone is trying to take your gun is feeling the attack rather than seeing it, so more work should be done blindfolded."
Ounce of Prevention