it is a Browning .30 cal machine gun, M1919. The allies used it extensively in World War 2, and i think the mechanics of the weapon were used as a basic design for the Browning M2 .50 cal machine gun. Crazy stuff, it is actually belt fed, with actual belt, not linked together rounds like belt fed weapons of today, the rounds actually feed from a cloth belt.
The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." -George Carlin