Seems to me like here’s the gist of the matter:
1. You can probably work around the letter of the law in Boston and justify it to *yourself*. AR-10s, BRN-180s, AK-74s, etc. are all “fine” by the letter of the law. I emailed GOAL about this and they agreed, with a caveat: being protected by the letter of the law is probably not sufficient to avoid prosecution by Massachusetts LE.
2. I saw an interesting argument represented elsewhere, and figured I’d duplicate it here. The rule of lentity “is a principle used in criminal law, also called rule of strict construction, stating that when a law is unclear or ambiguous, the court should apply it in the way that is most favorable to the defendant, or to construe the statute against the state.” Arguably, since the Boston AWB contradicts itself on 1) the SKS (by exempting fixed-magazine rifles from the ban and banning the SKS) and 2) 6+ capacity pump action shotguns (by exempting “slide action” firearms but banning 6+ capacity shotguns by name), an individual who wanted to litigate either of these points would PROBABLY achieve a favorable verdict.
3) Because no one has been prosecuted under the Boston AWB (to the best knowledge of everyone on this forum, and elsewhere that I’ve read) there’s no case law or precedent to fall back on. By my view, that might be intentional - if they were to ever prosecute someone under the Boston AWB and lose, they’re almost certainly aware that everyone who chooses to abide by the Boston AWB as constituted would quickly pivot their collection to the clearer understanding of the Bylaw.
4) Because there’s no case law on the ambiguously -written Bylaw, and because no one has ever been charged, your risk tolerance is up to YOU. Some people will own AR-15s and feel comfortable, some will own AR-10s or AK-74s, and others still will only own M1 platform rifles, or others which are specifically not enumerated or “substantially identical” to enumerated platforms. The chances that you’re ever prosecuted for owning anything are astronomically low, but not zero. Risk-tolerate accordingly.
IANAL, and I don’t live in Boston yet, but I am going to law school in Boston starting this fall. My risk tolerance is pretty low, since my future bar passage and the rest of my career are contingent on not having criminal charges on my record. Now, that’s not to say that I won’t volunteer/fund a case as a plaintiff at the end of my law school tenure against the Boston AWB. In a post-Bruen world, that shit reeks.
Until then, PTR-91/HK G3 clones, M14/M1As, and Tavors are the name of the game for me.