Gregory,
Thank you and a Merry Christmas & Happy New Year to you and yours!
It IS ILLEGAL to possess in MA. Here's the MGL on it and where you can find all the other obtuse laws (sub the Chapter & Section to get the text for other laws). I was wrong, it was 1-10yrs penalty for the 1st offense!!
www.mass.gov/legis/laws/mgl/140-131m.htmChapter 140: Section 131M Assault weapon or large capacity feeding device not lawfully possessed on September 13, 1994; sale, transfer or possession; punishment
Section 131M. No person shall sell, offer for sale, transfer or possess an assault weapon or a large capacity feeding device that was not otherwise lawfully possessed on September 13, 1994. Whoever not being licensed under the provisions of section 122 violates the provisions of this section shall be punished, for a first offense, by a fine of not less than $1,000 nor more than $10,000 or by imprisonment for not less than one year nor more than ten years, or by both such fine and imprisonment, and for a second offense, by a fine of not less than $5,000 nor more than $15,000 or by imprisonment for not less than five years nor more than 15 years, or by both such fine and imprisonment.