It probably won't.
The trick they'll play is to slip it in during conference committee onto some larger bill, and not give members time to read the bill.
What if by one of those cosmic coincidences, some horrific "assault rifle massacre" takes place a week before the bill is voted on?
Maybe some crazy old veteran (a "right wing militia kook", naturally) on psychotropic drugs will shoot up a stadium full of people with a "machine gun."
That's the plot of my novel, anyway.