The confiscation upon death of the owner would necessitate a list of all firearms and who owns them. So we have registration, door-to-door search, or required search every dead person's home. They could require a tax stamp for every firearm to get it out and use it at the range or upon stop-and-frisk. That way they make money, and force registration.
The lawyer chose the word "can". Any firearm that "can" accept a magazine holding 15 or more rounds. Not designed for, comes with a magazine holding from the factory, or even available aftermarket. So that is everything that it would be physically possible to McGyver or build with an unlimited budget or resources.
So, this is really the "Revolver and Single Shot Preservation Act", because there won't be anything else.
Will it pass the senate?
Well, they will never:
...lock everything down and close everything but the big box stores, forcing everyone to stay at home and inside.
...force everyone to wear masks.
...force everyone to take a vaccine and make everyone show proof of vaccination to go anywhere or do anything.
...force everyone to throw away their gasoline cars, force them to buy electric cars, and then ban privately owned cars altogether.
...not only sell insect meat in stores, but take steps to ban mammal meat (excluding cannibalism), to force everyone to eat the bugs.
...put legislation in place to put the who in totalitarian control of the nation if they declare a global medical emergency (which is the ongoing state of being since March of 2020).