It creates a dilemma for retailers.

If they sell at their normal prices, then they will see these “flippers” hurry out the door with all they can carry to sell to some other person at a markup. Then that person adds a markup and flips the ammo again.
So, the flippers end up making more money off the ammo than the dealer who placed the order with his line of credit, pays rent, insurance, utilities, and wages for himself and any employees.
I have seen this **** happen with my own eyes, and I do not blame retailers for marking up their prices to slow down the opportunists, some of whom aren’t even shooters.