The set screw at the back of the trigger guard limitations over-vacation from the trigger and allows make immediate trigger manipulation that easier. Another delicate but significant alter needs to do with the recoil spring system. By shortening it, this shotgun may be outfitted with an adjustable artificial shoulder stock. https://mossberg-940-jm-pro-parts81357.blogminds.com/what-does-shotgun-12-gauge-3-1-2-mean-26863363