Does the Assault Weapons Ban still apply to SBRs?
Maybe. I'll try to present both sides of the argument.
The AWB does effect SBRs in MA argument: The MA AWB, just like the Federal one, effects "semiautomatic rifles" without any regard to barrel length and does effect SBRs. The MA AWB is at
140 MGL 121. The section of the Federal AWB that applies to rifles is 18 USC 921(a)(30)(B).
The AWB does not effect SBRs in MA argument: The problem with Massachusetts law is that it's poorly written. The MA AWB states, in part "“Assault weapon”, shall have the same meaning as a semiautomatic assault weapon as defined in the federal Public Safety and Recreational Firearms Use Protection Act, 18 U.S.C. section 921(a)(30) as appearing in such section on September 13, 1994". If you go read all of 18 USC 921(a)(30), it does define assault weapons, but does not define the term "rifle". Why does that matter? Because the MA law specifically references ONLY that part of the federal law, and not the federal definition of a "rifle". Therefore, we must use the Massachusetts definition of a rifle, from
140 MGL 121. The definition in Massachusetts law states that a rifle must have a barrel equal to or greater than 16 inches in length. Because your SBR, by definition, has a barrel less then 16 inches, it can't be a rifle under Massachusetts law, and can't be an assault weapon using the specific section of the Federal ban referred to by Massachusetts law.