“over a change in the definition of Sporting Purposes for a classification of shotguns that are technically NFA items - pistol grip shotguns without a butt stock.”
All pistol grip shotguns are NOT per se NFA items, although they NOW must be sold only to those 21 and older. The only ones retroactively (and WRONGLY! Thanks, Klinton!) reclassified as NFA items, as a taxable destructive device like hand grenades or land mines, are the “Stryker” style that have a permanently-affixed rotary drum in them. They are basically 12-shot revolver shotguns, good for self-defense.
“All pistol grip shotguns are NOT per se NFA items, although they NOW must be sold only to those 21 and older.”
That seems to be a matter of contention. What about items that are over 26” overall, but with a barrel under 18”? They are being sold as not NFA, and the companies have a BATF letter approving it.
http://shockwavetechnologies.com/site/?page_id=88
The Mossberg 500 Cruiser is classified as “not a shotgun” by the BATF.
http://www.tombstonetactical.com/catalog/mossberg/500-cruiser-shotgun-12-ga-18.5in-cb-black/
The issue at hand is technically, since a pistol grip 12 gauge shotgun has a bore over 1/2”, and it was not designed or redesigned to be fired from the shoulder, it does not meet the legal definition of a shotgun. Therefore, the Mossberg 500 Cruiser is technically a destructive device.