I fear the problem is being somewhat over-simplified.
The notion you can just shoot the threat of the barrel is not a solution. Certainly this is a great option if the opportunity presents itself, but in my experience most people are smart enough not to get in front of the muzzle.
Likewise, discharging my long-gun to achieve a stunning effect strikes me as a bad idea. I have been close to the muzzle of more than one weapon when it discharged and, while unpleasant, it was not incapacitating. Combined with the fact that you are responsible for the projectile(s) that are sent wherever, I see little to be gained and much to be lost. Do you really want to be rolling around on your kitchen floor at 3 a.m. touching off rounds from your AR or shotgun? I think not.
Based on my experience, long-gun retention involves one of two scenarios. In both, the long-gun is invariably forced into some variation of a port arms position almost immediately, "negating the shoot him off the gun" solution. I would note that few to none of the individuals involved in attempting the take-away during the training had any significant experience with disarming someone armed with a long-gun.
The first situation involves a take away attempt by an individual (attacker) who is larger than the individual in possession of the gun (defender). In this situation, when the defender failed to mount an effective response immediately, he almost always ended up with his back against a wall or on the ground with the attacker on top of him. Occasionally, if the defender was slung into the weapon (and light enough) he was bounced off of walls and furniture before ending up on the ground. In virtually every instance, the defender having his back to the ground/wall resulted in the loss of control of his weapon.
The second situation involves a take-away attempt by an attacker who is the same size or smaller than the defender. In this case, when the defender failed to mount an effective response, it was a coin toss as to who ended up against the wall or on top of whom. There was a significant decline in the number of people being taken for rides by the sling. Again, the determining factor was who ended up with their back against the ground/wall.
The difficulty increases exponentially when there is more than one attacker.
As little as four hours of instruction can provide an individual with the necessary tools to defend his long-gun with strikes or by transitioning to a pistol or knife. I am partial to the Acitve Countermeasures system that Heckler & Koch's International Training Division was teaching, though I do not know if they still offer the training.
Realistic long-gun retention training is eye-opening and valuable training. That said, I can think of a number of skills I consider more important to acquire first. Still, if the opportunity presented itself, I would not hesitate to gain this skill.
Just one man's perspective....
