IIRC, short barreled shotguns by definition have shoulder stocks, while AOW shotguns do not. The latter have the $5 tax. Think about what you actually want a pistol-grip-only shotgun for, and realize that in general it's not particularly useful.
I bought this Mossberg 590 Mariner AOW from C3 dealer
Allan Kirchmer:
I'm also tempted by the
Serbu Super-Shorty:
Check your state's laws on such items; subtleties may allow or disalow such arms. Read
Bardwell's NFA FAQ. Peruse
Tom Bowers' Subguns Board. Read and contribute to the
1934 Group's lawsuit to remove the much-abused CLEO-signoff requirement for Class III transfers. When you're ready to buy, contact the dealer of your choice and just work through the paperwork he gives you.