The set screw in the back of the trigger guard limitations about-travel on the trigger and allows make quick trigger manipulation that much simpler. I don’t realize that he’s capable of firing just one shot, and I suppose doing so will be anticlimactic. What he does do is fire pairs. https://mossberg940jmforsale02468.blogunteer.com/28612749/what-does-shotgun-12-gauge-3-1-2-mean