Yes, you can own some of these in Massachusetts… kind of.
Unfortunately, since Dec 2017, the AG has determined that MA Dealers may no longer transfer SBR/SBS to mere mortals. (IE: Anything on a Form 4) That includes LE! MA now applies the same rules that apply to pistols to NFA items, so these now have to be on the EOPS roster to be transferable. Fat chance of that happening. Silencers are also restricted to LE and dealers only.
This ruling does NOT prevent you from legally creating someForm 1 items. We do provide gunsmithing services if provided with copies of accepted tax stamp applications.