While it's been several months since last hearing anything about America's Army for Linux, I heard this morning from the team that the game just very recently got the game compiling and running on Linux after being faced by some delays. While it's working, it will still take some time before it's ready for external testing, but they are now putting more effort into their Linux and Mac ports.
There's anticipation that the America's Army port on Linux could be ready for beta testing on Steam within the next month.
America's Army is a free to play game that's long been in development by the US Army. The latest incarnation, America's Army: Proving Grounds, is powered by Unreal Engine 3. Years ago there was a Linux port but it hasn't been that way in about a decade. It's great to see the OS X and Linux ports finally getting turned around for 2016. More details when we have it.