Bills of attainder and bills of pain and punishment are forbidden by the US Constitution. SCOTUS has ruled that states may not pass these laws in Calder v. Bull (1798).
C’mon, there has to be at least one honest lawyer who is not chasing ambulances or channeling the dead. Fight for our freedoms.
Definition: A legislative act that singles out an individual or group for punishment without a trial.
Unfortunately this is not one, nor is it, technically an ex post facto law. It would only punish possession, etc, after the date of enactment. It might be a "taking" law, in violation of the Takings clause of the fifth amendment. Have to see more details to tell. But it's in gross violation of the Second Amendment, which the Supreme Court has ruled applies to the states as well as the federal government. So if they are willing to ignore that, they'll ignore the more esoteric violations of the Constitution as well. New York's Constitution has no RKBA provision.