Think it's difficult with any certainty to predict today where a Biden administration will go on gun control. Two upcoming events will likely provide near term insights. First, the announcement of potential cabinet positions which has recently begun. Certainly the AG and head of DOJ is key. Secondly, the outcome of the two Senate races in Georgia and thus control of the Senate. Republican control of the Senate is key to limiting legislation. And finally, insights into a few related cases coming before the Supreme Court down the road.
That said, any executive order, law or regulation passed is only effective as embraced by the people. And while some will automatically comply with any call to register or sell back their guns and magazines or to pay a weapon tax, suspect the majority of owners will simply ignore the effort. And who would enforce it? Your governor? Your local sheriff or police officer who lives in your neighborhood and whose kids go to school with yours? The national guard reservist next door?
Certainly, the government can impact the availability of future weapons and ammunition. Not sure they could do anything better than the current marketplace. Current demand is the highest it's been in decades, manufacturer backlogs are growing daily but given time, the marketplace will self adjust to demand. That's capitalism.
Think the other thing to consider is stockpiles of weapons and ammunition already in people's hands. Suspect many reading this thread have a lifetime's supply on hand. Plus people have been hand crafting weapons for decades and reloading components are easily made if unavailable in the marketplace. Also to be consider is the number of weapons for which there are no record of ownership. Background checks are a relative new thing.
Finally, the new administration should tread carefully on overarching restrictions that will drive this entire industry underground. They would be wise to remember the days of prohibition. Life goes on!
Regards