While your state might not recognize retroactive domestic violence gun possession prohibition, federal law does. Hence, ATF can arrest in your state for violation of 18 USC 922(g)(9):
GUN BAN FOR INDIVIDUALS CONVICTED OF A MISDEMEANOR CRIME OF DOMESTIC VIOLENCE -- 18 U.S.C. § 922(g)(9)
The 1968 Gun Control Act and subsequent amendments codified at 18 U.S.C. § 921 et seq. prohibit anyone convicted of a felony and anyone subject to a domestic violence protective order from possessing a firearm. The intended effect of this new legislation is to extend the firearms ban to anyone convicted of a "misdemeanor crime of domestic violence."
This bill passed with almost unanimous support and represents Congress's recognition that "anyone who attempts or threatens violence against a loved one has demonstrated that he or she poses an unacceptable risk, and should be prohibited from possessing firearms." Congressional Record, p. S11878, September 30, 1996. This new provision affects law enforcement in three interrelated ways. First, it will assist in preventing those individuals who have demonstrated a propensity for domestic violence from obtaining a firearm. Second, it will assist law enforcement by providing a tool for the removal of firearms from certain explosive domestic situations thus decreasing the possibility of deadly violence. Finally, it will serve as a federal prosecution tool in certain situations where alternatives have failed.
Qualifying Offenses: As enacted the statute defines "misdemeanor crime of domestic violence" (MCDV) as any state or federal misdemeanor that -
"has, as an element, the use or attempted use of physical force, or the threatened use of a deadly weapon, committed by a current or former spouse, parent, or guardian of the victim, by a person with whom the victim shares a child in common, by a person who is cohabiting with or has cohabited with the victim as a spouse, parent, or guardian, or by a person similarly situated to a spouse, parent, or guardian of the victim."
This definition includes all misdemeanors that involve the use or attempted use of physical force (e.g., simple assault, assault and battery), if the offense is committed by one of the defined parties. This is true whether or not the statute specifically defines the offense as a domestic violence misdemeanor. For example, a person convicted of misdemeanor assault against his or her spouse would be prohibited from receiving or possessing firearms. It is anticipated that this issue will be subject to litigation. In the event of such litigation, the Terrorism and Violent Crime Section should be notified so that assistance can be provided.
Retroactive punishment is prohibited by the Article I Section 9 Paragraph 4 of the United States Constitution.