I assume, that before the police begin these raids, The gun controllers and the police are going to move themselves and their families into a green zone. It's a small price to pay for such an important and sacred outcome.
I believe the plan would be to make a few high profile examples to keep the remainder in check. High profile would be max force with unhappy ending for targeted gun owners. Press would be enlisted to supply the propaganda (as usual). Show of force in the community with fed supplied APCs would also be part of the dog & pony show. If things got too bad NG would be called up. That said, all sides should understand no plan survives first contact. Hope we dont have to experience confiscation but it seems a segment of our society is hoping so. THe outcome wouldnt be at all good.