Department of Homeland Security
Office: Transportation Security Administration
Location: Headquarters TSA
Estimated quantity is approximately 4,800,000 rounds of .357 Sig duty ammunition per year, totaling 24,000,000 Million over the life of the contract.
Now Homeland Security Is Ordering 24 MILLION Rounds of .357 Sig "DUTY" Ammunition
So the Department of Homeland Security has a contract out for 24 million rounds of .357 Sig ammunition, apparently they did not want to use the term "Hollowpoint" so they called it "Duty" ammunition instead. But obviously they did not specify "Training" ammunition, which normally is cheaper.
Outside of certain governmental organizations like the Federal Air Marshalls, and the Secret Service, .357 Sig ammo is not a vastly popular round. It is basically a .40 caliber case necked down to accept a 9mm bullet.
Link : https://www.fbo.gov/index?s=opportunity&mode=form&id=c0de8ce5905df7f3bc9f2427c22131e9&tab=core&_cview=0