Just What is DHS Going to Do with 1.6 Billion Rounds of Ammo?

Stories of government agencies like Social Security, buying 174,000 rounds, the National Oceanic and Atmospheric Administration buying 46,000 rounds have bounced the Internet.  But this Forbes story on the DHS purchase of 1.6 Billion rounds makes the other stories look like a small purchase at your local gun shop.  Forbes puts a little perspective on this number:

...Also reported elsewhere, at the height of the Iraq War the Army was expending less than 6 million rounds a month.  Therefore 1.6 billion rounds would be enough to sustain a hot war for 20+ years.  In America.

This subject came up on Tom Gresham's Gun Talk program yesterday.  Without speculating any conspiracy, Gresham noted that one problem is the federal government requires federal law enforcement to practice with the ammo that they carry.  That means hey are forced to practice with the more expense hollow point ammo they carry rather than less expensive ammo.  How's that for being fiscally responsible?

DHS explains their purchase this way:

Peggy Dixon, spokeswoman for the Federal Law Enforcement Training Center:  “The training center and others like it run by the Homeland Security Department use as many as 15 million rounds every year, mostly on shooting ranges and in training exercises.”

At 15 million rounds a year (which sounds like a lot to this writer as it did to the Forbes author), 1.6 billion rounds would last well into the next century.  It begs the question though, given we are being told because of the "sequester" we should expect long lines at TSA airport checkpoints, just why is DHS purchasing such a rediculously large amount of ammo that it's various agents could not be expected to expend for almost 100 years?