JRT
NES Member
there seemed to be an opinion that even though it came from the manufacturer with that 14" barrel you could not NFA paper it to a SBS. Not sure the argument made sense to be, but it seemed to be consensus among those who are normally correct about MA law.
I don't know anything about Mass law but I'm confident that gun would be more fun as an SBS. Watching the videos of it being fired with that little grip causes me pain.