The only rationale that I’ve found for this is virtually unrecognizable as logic. It is over 26” which is the length beyond which the ATF recognizes a weapon as not being concealable. If it was less than 26” it would be considered concealable and then an AOW. The goofy assertion is that if you prove them wrong by concealling it, then it must be an AOW rather than a firearm in that circumstance.
Since it's on Mossbergs website it has probably been written somewhere by ATF, but I don’t know where.
As with most ATF stuff, it isn't law, it’s their interpretation of the law. If it ended up in court it’d be fun to lay out 10 shockwaves and ask the ATF expert witness to identify which ones are AOWs. Obviously he or she wouldn’t be able to do it. The downside is that to get to this you’ve probably spent better than $250k.
Oh, and the difference between concealed and stored in a vehicle is a gray area, but if it is handy then I think it’s more likely concealed than stored.
Didn’t
@Gunbelt make a holster to open carry a shockwave?