DHS officials testified last week that it was only planning to purchase up to 750 million rounds of ammunition for training centers and law enforcement over the next five years. The agency’s spokesman, Peter Boogaard, told Congress that the media reports are ‘misleading’. But Boogard also mentioned a second five-year contract for up to 450 million rounds of ammunition for law enforcement purposes. Together, the two DHS contracts for ammunition would result in purchases of up to 1.2 billion rounds of ammo.
You are overlooking the key words in your own post: The DHS purchase orders are for a "not to exceed" quantity. It has not actually purchased 1.2 billion rounds and it is not required to purchase 1.2 billion rounds; rather, it has the option to purchase 1.2 billion rounds over a five-year period. Still, I would be happy if Congress defunded and disbanded the DHS today and short of that, the House ought to limit DHS funding for ammo to 10 rounds per officer per year.