Yes, the forfeitures are supposed to be in connection with drug investigations, but there's a loophole. The property, including firearms, can be seized early in an investigation. And the investigation may later conclude without any criminal charges being filed. By the the time the investigation concludes, the seized property may have already been forfeited, with ownership transferred to the government.
What protections do we have that investigations are opened in good faith, and that they aren't primarily conducted as a means toward confiscation of guns, cash or other private property?
Should the government (or even a tiny group of agents) chose to go rogue, it appears some amazing unchecked powers are available to employ in abusing citizens and their private property rights.