Guns that only fired one shot was starting to get irritating, and it was only a matter of time before someone solved the problem.  They were many attempts, double barrel shotguns, so-called harmonica guns (John Browning's dad came up with one), and the worst solution of them all, carrying 3 pistols and a rifle at the same time. In 1855 Britain, TW Treeby built an early form of 54 caliber "chain gun".  A percussion rifle, it had 14 chambers that revolved around the receiver, and it was cool and clumsy all at the same time.  Keeping it in action was doable, if you had 3 or 4 loaders behind you.  Of course the dangers would be obvious if one had experienced a Colt percussion pistol that let all the chambers go at once, which did happen from time to time.   A thirty shot Treeby had been shown to the British Army but they didn't bite, they thought the gun wasn't powerful enough at the time.  Treeby did have 2 patents on the gun, in 1855 and 1858.   There is one in a museum in Hampshire, but not really clear which one it is in.  Can't be many of them.  The guys over at Forgotton Weapons got their hands on one and show it off in this video.