Victim reports agg assault. Claims firearm was used. Suspect is felon, so shouldn't be in possession. Search warrant obtained and executed, firearm and other offenses found.

Victim gives videotaped recant to private investigator within a couple of weeks of report that started all this.

Is there any effect on the felon in possession and other offenses found during execution of the search warrant?

Is the victim recanting that she actually saw the weapon, or saying she never told the police that? If she's saying she never saw the weapon, then that has no effect on the validity of the warrant. She still told the police she did, and assuming they had no reason to doubt her credibility, they had PC to believe he had a weapon. The police aren't expected to divine that she will later change her mind about what she saw.

She says it never happened.

But since she said it after the police acted on her representation, the SW should be good for the other offenses. Of course, the Agg Assault got closed out.