It falls into a BATF loophole in the definitions ". It’s the same position that ATF has always taken regarding PGO firearms that fire a fixed shotgun shell that have NEVER had a buttstock attached to them—they’re NOT shotguns! They’re simply firearms. As such, they don’t necessarily need to have 18″+ barrels on them to remain out of the purview of the NFA." http://shockwavetechnologies.com/site/?page_id=88%2F
mossberg.com/wp-content/uploads/2017/03/Shockwave-Letter-from-ATF-3-2-17.pdf --------: ffl123.com/no-nonsense-non-nfa-14-inch-scatterguns/

Same as the Shockwave Edward(basically it's all in the grip configuration not being a shoulder stock). The same concept as an AR Pistol with a "Brace" and not a traditional shoulder stock not being classified as a SBR (Short barreled rifle, NFA item). ATF decision applies to both : mossberg.com/wp-content/uploads/2017/03/Shockwave-Letter-from-ATF-3-2-17.pdf --------: ffl123.com/no-nonsense-non-nfa-14-inch-scatterguns/