Well there hasn't been one announced yet soooo..... Don't panic buy that is all i gotta say.
I'm gonna stop you right there, you just said an AR-15 is a high-powered rifle. It is obvious you don't know anything about guns and I shall ignore anything you say from this point on.
You might wont to pick up a lower or 2 if you can. That is the part of the gun that has to be registered and has the S number. If they ban parts this will be first on the list and almost impossible to find. You should still be able to find other parts tho.