Common use for specific models shouldn't even be a thing. Is it an arm useful in fighting tyranny? Great.My 50/50 bet is that maryland based on the statements of does this apply to ar15's only vs the whole ban. They take a loss and allow Ar's and try to have the case mooted.
A quick change of the law to allow AR's ( maybe Ak's ), as they are obviously common use, they cant fight that. But keep the rest so the ban is still effective for a lot of guns they dont like. Its easier to fight HK94 and 91's ( or many other guns ) as they are not as common as ar's.
This also lets other states be able to fight their bans the same way. If MD fights it all the way and looses it goes to scotus and you know their afraid of that. Other states will pull what happened with some of NY laws and say give up so we dont all take a loss.