Quote Originally Posted by SAnd View Post
Or it could be a ATF agent that doesn't understand how regulations and laws have been enforced in the past. You can't assume the ATF is correct given their history of inconsistent actions and flip-flops in the past.

My understanding is that in the past the ATF ruled that the bore for for a Destructive Device is measured across the top of the lands, not across the bottom of the grooves. The rifling for a 28 gauge is .498 across the tops of the lands. That's less than the magic half inch.
It has .052" deep rifling? (28 Ga = .550") That seems a bit excessive- but everything about it is excessive... put it next to a .410 Judge, and it makes them look tiny!
The other hurdle to pass muster as a pistol- what handgun round is it chambered for? Hard to pass it off as a pistol, when it only takes a shotgun round...

I certainly don't have any insight, and don't always assume the ATF is always correct... I was just guessing some more, in a way that doesn't involve instilling a panic-driven buying frenzy