Released Jan 15 2009 on the HK-USA website:
http://www.hk-usa.com/military_products/mil_newsroom_01152009.asp
The existing facility is Wilcox Industries.
I was wrong in some of my info, from what I understand, the HK416 and HK417 are still made in the Oberndorf plant. I am unsure if they also make them in the US.