why I never came across this until recently, I have no idea.
Does this seem to put the kibosh on any ak/ar bans?
There are cases still pending because of the fascist state of NY attempt to destroy the 2a, but that's nothing new.
However the constitution and supreme court rules have enough wiggle room in their wordings such that it is the right of the lawmakers to argue on the basis of those wiggle rooms.
Like most rights, the Second Amendment right is not unlimited. It is not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose: For example, concealed weapons prohibitions have been upheld under the Amendment or state analogues. The Court’s opinion should not be taken to cast doubt on longstanding prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms. Miller’s holding that the sorts of weapons protected are those “in common use at the time” finds support in the historical tradition of prohibiting the carrying of dangerous and unusual weapons.