Well Mike, one of my friends called Michaela at the Firearms Records Branch down in Chelsea (617-660-4789) and she said that regardless of what the Feds say--State law is State law as far as rifles are concerned in Mass. When you build up a short-barrelled rifle on a Form 1 or buy it from a CL3 dealer, it still must conform to the State's assault rifle description. So, it has a short barrell--it still must be compliant with State law. If you doubt it--give her a call and report back to us what she tells you. Let's be careful out there!