There's much of his plan I don't see happening for various reasons, not the least of which is the blue wave bought a lot of "assault weapons" this year. Enforcement is getting less and less likely. Really unless you live in the 16.5% of the nation that voted blue, its highly doubtful anyone is going to enforce.
But one thing he will do by executive order is ban the import of semi-automatic firearms. That includes a lot of really nice shotguns, as well as sporting firearms that have no military association whatsoever. It will also inhibit domestic makers from using foreign manufacturers for their low end semi-automatic firearms. He has said this is day one for him, along with 100 days of the mask. The precedent has been set that this is established executive action, so legal questions would be hard to press.
Second thing he may try to do by executive order, which has more room for challenge, is ban the internet sales of guns, ammo, parts, and supplies ... to include reloading supplies. For all the blue Fudds, this means no more brass for the swede or Krag or even 30-30, as your LGS doesn't sell enough of them to keep them on hand, and the manufacturers can't make enough profit on them to keep them in production. Maybe a custom run, limited number, elevated price. Same with powder, primer, and replacement parts for those nice old guns. Have to go through the LGS to get to Numrichs, instead of ordering direct.
Everything after that will take congressional support, and blues got spanked in congress so they are going to be risk adverse heading into 2022, especially if Georgia gives two more red senators.
