Future sales sure, but if people legally purchased and now owned such items pre ban, a grandfather clause must be enacted or fair market compensation.
If neither of those things are granted it opens the entire thing up legal action which then can set precedent..
(given an unbiased SC, if it got that high)
If the bump stock ban is any indication, it looks as if millions of gun owner are going to be out hundreds of millions of dollars, via executive fiat.
Ray