FUCK THESE PEOPLE
END COMMUNISM NOW
		
		
	 
The president does not have the authority to do this.  The Courts will shoot it down, no pun intended, almost immediately.  I am sure red states would ignore it.
But people give the Australian buy back plan too much credit.  My understanding is they only collected about 20% of the guns in Australia. Then, a black market of guns sprung up.  Australia claims success because of a decrease in gun violence, but I am not sure that is all attributable to the gun buyback.
Remember too, Australia also implemented a very rigid COVID lockdown policy, even incarcerating people (quarantine) in an attempt to stop the spread.  Apparently they do not have a strong constitution like the US to protect individual liberty.