Bump firing done from the hip with a finger worked into the belt loop
Bump Firing with a thick ruber band - Excellent!!
The term “machinegun” means any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger.
I can see bump firing as being a machine gun. You cycle the trigger one time and it keeps shooting to the mag runs dry or you do something to stop the recoil. So even if the "item" is not banned... such as a "rubber band".... it is now a machine gun as far as the definition goes.