The second one is an "Assault Weapon", not Rifle. This is why it was called the Assault Weapons Ban.

See [0], "a United States federal law which included a prohibition on the manufacture for civilian use of certain semi-automatic firearms that were defined as assault weapons".

"The Act prohibited the manufacture, transfer, or possession of "semiautomatic assault weapons," as defined by the Act."

0: https://en.m.wikipedia.org/wiki/Federal_Assault_Weapons_Ban