After voluntary window expires, send authorities after registered ones, or just send fines for a while.
This part doesn’t work with your “solution.” Do you expect the police to enter people’s homes and take their guns?
Iterative. Fines, court dates, warrants when it comes down to it. Sentencing enhancements for crimes.
I wouldn’t send authorities into homes, no.
Fines, court dates and warrants do not take firearms out of the hands of people that would rather die than give them up. You’d eventually need SWAT tasks force level initiatives to go and kill resistors eventually; I find that highly unethical.
And there it is. Exactly what I said was going to happen. What was the point of this exercise?