Olin Corporation (which trades under the Winchester Ammunition brand) has just been granted a patent (#8161886) for a 12 gauge shotshell design that would be used in conjunction with a barrel insert in order to allow the firing of small-caliber bullets through a rifled barrel from a 12 gauge shotgun.
http://www.thefirearmblog.com/blog/...ts-concept-to-circumvent-hunting-regulations/
hunting with a "rifle" in MA! banned in 3... 2... 1... [sad2]