One of the major ammo manufacturers put it this way: 7 million first time gun buyers in 2020, but an average of 2 boxes of ammo to go with their new gun. That is 700 million rounds of ammo that are being bought this year, over the expected purchases from people who already owned guns, but see things going sour and try to buy more to stock up. The manufactured more ammo this year than they did last year, but they just cannot keep up. Once the idea of scarcity started to drive people to buy all they could get, there was no way to keep up.