We all hear or read the second hand stories of AKs turning up all over the world still in use. But often the stories of M16s from long ago are not talked about as much. That does not mean it does not happen. Recently some one shared on facebook a picture of a XM16 Colt still being used in Cambodia.
Left there during the war, it still serving its owner all these years later. A bit rougher than it left the US, but still working. And with some customizations! Apparently even in Cambodia the urge to customize the AR15 is hard to resist.