My 2 cents worth:
When I was in the Security Police armory at RAF Upper Heyford in the UK we had 100,000 rounds of 5.56 on hand, another 100,000 of 7.62, and about 1,000 40mm, in the armory itself. In a bunker located in a secure area of the base we had more than 2 million 5.56, another 3 million of 7.62, and I don’t remember how much 40mm HE, all were war reserves. And this was an AIR FORCE base, not marine or army. And the Air Force really does not shoot all that much. The war reserves were expected to last less than a week, so similar caches were available at every base in Europe.
The USCG, a segment of DHS, is shooting all the time and I can’t even conceive of the number of round they go through annually. And one must remember that the 2.4 billion rounds is contracted to be delivered over the next 10 years.
Honestly, it’s not really all that much. Given the number of actual shooters that DHS employ’s I don’t find it at all suspicious that they are asking for such a huge number of rounds.
Ron