Legal
AOW (Any Other Weapon)
A catch-all NFA category for concealable or unconventional firearms that don't fit other classes — transferred on a $5 tax stamp.
'Any Other Weapon' is the NFA's catch-all category for firearms that don't fit the standard definitions — things like pen guns, cane guns, smooth-bore pistols, or certain firearms with both a vertical foregrip and a short barrel. Despite being NFA items, AOW transfers carry a reduced $5 tax stamp (though making one is still $200).
The AOW category is nuanced and easy to trip over; adding a vertical foregrip to a pistol, for example, can create an AOW. Anyone modifying a firearm in ways that might cross into this territory should understand the rules first, because possessing an unregistered AOW is a felony.