My perspective
It’s amazingly simple on the grandfathering. I honestly am baffled why people are confused.
First, is the object an ASW: Under the new law pre Healey are not copies or duplicates of ASWs so are evaluated solely on features under the new law to determine if they are ASWs. This is important. All the 2016 language in the new law does is exempt pre Healey from being copies or duplicates. That is the totality of what it does. It even has two flaws saying they have to be “registered” and that it’s before 7/20;2016. Since MA does not as of 2016 have registration, just recorded transfers, AND the system is fundamentally incomplete and flawed, this is a problem. But let’s pretend this is ok and a fa10 means registered. All the language does is exempt from copy or duplicate. You still have to evaluate based on features. Also the pre Healey language only covers the person who bought it and owned and registered it before 7/20/16. Worth noting that a lot of people bought ON 7/20/2016 and this does not help them. But in practice this language is useless since all the guns fail the feature test under the new law.
Post Healey are copies or duplicates so therefore most are now ASWs based on the feature test and being copies or duplicates. That barrel shroud language wipes everything out.
Second, is it lawfull for you to possess. If it’s not an ASW, yes. If it is an ASW, was it lawfully possessed on 8/1/24. If it was lawfully possessed on 8/1/24 then it continues to be lawful to possess.
That is what the law says. There is no ex post facto anything going on. Nothing is retroactive or changes what WAS legal or not. It’s not hard to understand what the law says and means about ASWs.
Now the practical.
But we still have a couple challenges. If the law takes effect before 8/1, then NOTHING is grandfathered and everything gets evaluated based on the new law. That causes a huge constitutional problem as a taking. But because of the new ASW definition for rifles with the barrel shroud feature, most are toast.
If the law takes effect after 8/1 you can still buy stuff but it won’t be grandfathered is a concern. BUT if the dealer lawfully possessed on 8/1 then it meets the grandfather criteria. It does not say you, just that it was lawfully possessed ON 8/1 by LTC holder or state dealer.
The final issue is about right now. Are post Healey ARs lawful to possess right now. If no, then still no. If yes, then yes after new law. The argument about Healey is not that it was written into the new law, but whether the 2016 press conference meant something. People who say post Healey BECOME illegal under the new law are wrong. Post Healey are only illegal under the new law if they are already illegal.
This is not that hard. We are seeing a lot of people with logic failure and/or confirmation bias. A number of GOAL lawyers believe post Healey are already illegal so they come up with arguments that new law codifies this. It does not. It just exempts pre Healey as not a copy or duplicate.
All the new law language about pre Healey is a total ho-hum. It just makes some guns extra legal. It changes nothing. Because of before 7/20/2016 and the new criteria for features, it just doesn’t matter. Everyone relies on the 8/1 lawfully possessed language.
So bottom line, if post Healey are illegal now, they remain illegal. If they are legal now based on features, they remain legal.