OK, first I'm going to qualify what I'm about to say by stating that I don't own a gun, have never owned a gun, and have no intention of ever owning a gun. I don't need one and I've no desire to own one. Someday that may change but that's where I'm at....
Going forward though, "An assault rifle would be defined as something that is on the list of assault rifles?" Really? Who makes the list and what is their agenda? That's a scary statement. Depending on who makes the list and what their agenda is, anything can be put on that list and it automatically becomes an assault rifle by your definition. What are you willing to give up once it's declared an assault rifle?
We actually have that in Maryland. There's the list of "enumerated weapons" (mostly 5.56mm AR-15 variants) the legislature has banned (by make and model), and the State Police, who have responsibility for enforcement, are allowed to ban "copycat weapons."
As a result, the good legislators of Maryland have protected their adoring constituents from me having this 5.56mm clip-fed semi-auto rifle taking 30- or 40-round magazines or 75-round drums:
but that's OK by me because I can and do have THESE 5.56mm clip-fed semi-auto rifles taking 30- or 40-round magazines or 75-round drums:
Do you feel safer yet?
I also have this clip-fed semi-automatic rifle in 7.62mm:
because the good legislators of Maryland were so intent on banning "the AR-15" that apparently nobody bothered to tell them that a 7.62x51mm, clip-fed semi-automatic rifle is every bit as rapid-firing, and far more powerful, than a 5.56x45mm clip-fed semi-automatic rifle.
So in the end, it's all good. The Maryland liberals feel all warm and smug now that they're protected, and I have my high-capacity guns.
Yay.