A friend told me that he read in "shooting insider" magazine that the ammo companies in the US are producing a billion rounds per week.
Sounds high to me. According to this industry report
, annual sales of small arms ammunition are typically around 7 to 10 billion in the U.S. Although according to that same report, the Army needed 300 million rounds *per day* in 2005, which sounds impossibly high to me.
I did find a lot of references online to the "one billion per week" figure, but they may all just be parroting the same (possibly flawed?) source. Personally, 52 billion rounds per year sounds too high, even with all of the manufacturers working at capacity.