These recent laws are being written to try to force the supreme court to clarify the opinions from Heller about bans on certain types of weapons. "Assault Weapon" has no agreed upon definition and they want the court to define a marker(win or lose) they can ban around.
The left is pushing this hard now because the 5-4 split is likely going to 6-3 before the end of a second Trump term and there won't even be moderate Kennedy Swing vote. The left should have hedged and had RBG step down. I have a feeling that Hillary made them double down and wait on Ruth so she could put 4 or 5 justices in place for the next 40 years. They never thought she would lose.