Why would the 2nd apply to electric doodads? A firearm, or “arm” is pretty clearly defined.
Electric doodads? Certainly not an arm. Batt powered sex toys have more in common technologically with a taser than a firearm does.
Electric doodad rifles that shoot discs with stored electrons are already out there, not super deadly - yet. Definitely rapid fire capable.
And high powered air guns that shoot large, 1/2" - 3/4" slugs are also not considered a firearm. Seriously deadly though!
The definition of a 'firearm' is and will become rather problematic as nature always finds a way around a constraint!