I doubt there's millions. Maybe a few hundred thousand TOPS in the handful of states where they're banned. They haven't been rounded up because there isn't a serious priority in law enforcement to do so. They will change when the orders are given.
When a man has to choose between his wife, his children, his home, and his livelihood or his AR-15, you'll see.
I have not seen any evidence that will convince me differently. Meekness is epidemic among conservatives. We talk a great game but could learn something about mettle from Antifa who are out there in the streets, punching people in their faces. They walk the walk.
The number is 75 to 90 million. based on the component manufactures it is way higher.