Well, in the handgun world, in the 1890s with Browning's guns.
And 1896, with Mauser's broomhandle pistols and carbines. There was also a "712" version built which took 20 round detachable magazines and full-auto capable.
BORDERLANDS: THE GRAPHIC NOVEL
A story about a man, his harrowing journey, a vast frontier, and a great struggle.