The plaque on the Gatling gun, I believe, said 1860. I have read on this forum they had been prone to jamming. The feed mechanism on this early model was very simple. Last year I was at a gun show in Maine and they had a circa 1880 Gatling gun with a much more complicated feed mechanism. From what I have heard, this later model rarely jammed. They had a whole room with just machine guns. Most had rates of fire around 600 - 800, pre WW2. There was one German machine gun which was light in weight and had a 1250 ROF. It was pretty impressive