I was going to challenge the assertion that US forces were equipped with the
Belgian Lewis machine gun... then I thought I'd better check!
Sure enough, I found that when Colonel Lewis could not find a buyer in the US, he went off to Belgium in 1913. (I'm learning just how accurate dragon500ly can be!)
However, it saw most service in British hands.
For the most extreme example in history of a man's life depending on his weapon, just do a Google search for "Louis Strange."