For as much emphasis as there is on ensuring you only get 1 shot per "trigger action", aren't there a lot of ways to make that happen?
Setting aside the obvious (shotshells, binary triggers, volley guns, etc.), there are still others:
>multiple trigger actions in advance, stored and activated by the movement of the trigger-shaped safety
>spring-tension trigger (the further back the trigger goes, the more "actions" the trigger takes)
>automatic triggers (let the gun decide) which pull themselves as they fire
Would the law apply to these also?