Actually banning firearms purchasing is the kind of mess that "Universal 2FA" supporters* support up until they realize the logistics of what it would entail and quickly bounce back because it might impact white people.
But what does happen is the affected groups see the threat of a ban. So those who are particularly scared rush out to buy guns while they can (and so do the people who want them dead). Which bumps up sales and makes the firearms industry happy.
But it also means cops have an excuse to assume every single trans person is packing a machine gun. So no knock raids and executions increase.
*: Except for basically the select few gun nuts like Karl at inRange (Kasarda?) who actually genuinely believe everyone should have the right to own a gun and has gotten shit on and shunned by much of the "firearms community" for expressing these thoughts. With respect to trans people, even.