A full auto mechanism is different. If the trigger remains retracted, the auto-sear releases the hammer after the bolt goes into "battery" and allows another firing sequence to begin. If the trigger is released, the auto-sear holds the hammer back until the trigger is operated again.
In each case, semi-auto or full-auto, the design of the fire control mechanism dictates whether a single shot or multiple rounds get fired with a single depression of the trigger.
The "bump stock" provides a sloppy way to use the motion of the WHOLE RIFLE experiencing recoil to "reset" the trigger between presses. It is extremely inaccurate and requires some skill to achieve a burst of fire. It's stupid range toy for people who have lots of money to burn dumping magazines full of ammo.
Amen! Plus there are very few places that even allow "rapid" fire.