They are probably going to need some serious life insurance and hazard pay to go for direct confiscation.
The do not issue warrants for these confiscations. They go to peoples homes and ask them to come inside. Then they pressure them to turn the guns over.
Most people do not know enough to say “Do you have a Warrant?” Then “Come back when you have one.”
The first step of resistance at your house is to say NO! to entry without a warrant.