Why does Homeland Security need 1.4 billion rounds of ammunition?

◼ The Department of Homeland Security has purchased 1.4 billion rounds of ammunition- that is not a typo -- during the last six months. This includes 450 million rounds of .40 hollow point, 200 million rounds of .223 rifle ammunition, and 176,000 rounds of .308 168-grain hollow point boat tail (HPBT) that is used almost exclusively as ammo for sniper rifles. - Lee DeCovnick/American Thinker