Pretty sure he was trying to find out if he can legally shoot the 37mm or 40mm thingy that some fell the need to hang under the barrel of their AR.
I have my doubts that anybody cares, as long as there are no explosive rounds going downrange.
Without explosives in them, the rounds seem to me like they would be about as much fun as watching $20 bills burn, and about as cheap, too.
Good thing we all have different tastes, or it'd be a boring place, eh?
Cheers
Trev