LOL. I have a co-worker who has the same line of thinking as you. According to her, first the dissenters will be loaded onto trains and then taken to the camps.
Simple. Just look at pro 2nd Amendment letters to the Editor. Then at the following lists: Holders of CCW permits; former military personnel (especially officers); NRA membership lists; subscribers to pro-gun or conservative publications; and that's just a start. Since I qualify in all of the above categories, I figure I'm #1 on the list! There is an EXCELLENT book that covers all of this: Hope of the Wicked by Ted Flynn. I think you can get it from amazon.com. It's a huge book but reads like a novel. Very well organized.