The Perkins Steam Gun: 1000 rounds a minute -- in 1824! And nary a one fired in war. (You want nightmares for a week? The Civil War Between The States* with steam machine guns. --Like this one -- thankfully, one and only.) As for Perkins, he's pretty amazing.
Found at Lateral Science, q.v., and for the finding of which I must thank Carl Bussjaeger.
* Northerners, Southerners, fight quietly among yourselves over this terminology; given Indiana's deeply divided opinion during the Late Unpleasantness, I thought it only fitting.
One Evening On Kansas II
2 days ago