I totally get the surety of the 2nd amendment.
Regardless, I would have no problem with gun and ammunition sales NOT possible except face to face in a store, in the state where the buyer resides. And, I have no problem with a weapons sales person denying a sale to someone, without having to give any reason for the denial - I don’t have to sell something to someone just because they want it; the property is mine until I sell it and I can refuse to sell to anyone.
Except for baked goods.