Dog Gone at Penigma
The only way for seizure of an illegal assault weapon is through a court-issued warrant, and then only after a court hearing has ruled on the legality/illegality of the weapon. Simply receiving a letter that your request for registration was too late is NOT grounds for such a warrant, because there are multiple options for possible legal disposal of the now-illegal firearms, etc. That means that while you clearly had an assault rifle, etc. AT ONE TIME, there is insufficient basis to issue a warrant, because there is absolutely no information that shows you still have that firearm after receiving the letter, and the state themselves provided you with the information to act legally. The assumption has to be that you are legal and law abiding, not that you are guilty and unlawful. Otherwise you have grounds to dispute the legality of the warrant, and anything that results from it - or so I have been told. I'm not a lawyer, nor do I claim to be. However there does seem to be ample support for the basis and success of such a challenge in other contexts, in the form of what is in legal terminology, a motion to suppress under the exclusionary rule,and the protections of the 4th Amendment against unlawful search and seizure, as well as possible protection under state Constitutions.