I'm sure it's very easy to seperate out semi-auto sears from selective fire sears when it comes to writing an opinion. Those justices will make sure of that so I can't understand how it would be complex to protect AR's and still keep NFA firearms seperate. AR's in semi-auto configuration are common use, M4's and M16's with selective fire sears are not (even though they should be)
Question in the Snope petition:
Whether the Constitution permits the State of Maryland to ban semiautomatic rifles that are in common use for lawful purposes, including the most popular rifle in America.
The only parts that will be part of the issue are those that are defined as enumerated ban features.
If the court cements the Bruen methodology and further explores the history of longstanding, widespread arms bans based on lethality of an arm and its involvement in violent crime, they will find essentially nothing banning the possession of such weapons. The closest analogous laws would be the banning of carry of bowie and similar knives but not possession. This would necessarily be the basis of the historical review since the state's argument allowing the ban is that the enumerated features make the firearms too dangerous for the 2nd's protections.
Once the history of bans is explored, then we can show that 1934 is not within the Heller/Bruen timeframe for founding era analogous laws and that the 2nd is not limited to arms that fall below an arbitrary level of lethality set by the government.
Further, but for the NFA and the follow on Hughes amendment, machineguns would have proliferated into popular items similar to silencers today. This fact would be easily shown to be true with even casual polling of the gun owning public.
The government in many cases and, particularly, in Snope has argued both for and against Miller's finding that to be protected a firearm had to possess military utility even though Heller clearly shows that neither position holds - arms in common use are protected regardless of usefulness or uselessness with regard to the military.
But one would argue that machineguns fail the "in common use" test - they do, but only because the government impermissibly restricted access to them. Further, the fact that 175K of them are in circulation mostly from a time where a person had to pay a tax equivalent to a week's income or more on top of the cost of the arm in itself proves that machineguns are wildly popular and only uncommon because of government infringement.
Any case would need to be carefully curated in the proper venue to ensure an en banc circuit win since a grant of cert would be highly unlikely unless the government is the petitioner.