Volley gun
Two notable artillery-sized volley guns were developed in the mid-19th century, although neither was particularly successful in practice. Developed in the 1860s and based on an 1850s design by a captain Fafschamps, the French mitrailleuse is an example of a multi-barreled volley gun that could fire all of its barrels simultaneously or sequentially over a short period of time. Also developed in the 1860s, General Origen Vandenburgh of the New York State Militia designed a weapon that had eighty five parallel .50 caliber rifle barrels. After failing to sell the weapon to the United Kingdom, he reportedly sold a small number to the Confederate States of America, although there is no record that they were actually used. One Vandenburgh gun was located at Fort Fisher, North Carolina, and another reportedly at Salisbury, NC.
Revolver
Early revolvers were caplocks and loaded as a muzzle-loader: the user poured black powder into each chamber, rammed down a bullet on top of it, then placed percussion caps on the nipple at the rear of each chamber, where the hammer would fall on it. This was similar to loading a traditional single-shot muzzle-loading pistol, except that the powder and shot could be loaded directly into the front of the cylinder rather than having to be loaded down the whole length of the barrel. Importantly, this allowed the barrel itself to be rifled, since the user wasn't required to force the tight fitting bullet down the barrel in order to load it (a traditional muzzle-loading pistol had a smoothbore and relatively loose fitting shot, which allowed easy loading, but gave much less accuracy). When firing the next shot, the user would raise his pistol vertically as he cocked the hammer back so as to let the fragments of the burst percussion cap fall out so as to not jam the mechanism. Some of the most popular cap-and-ball revolvers were the Colt Model 1851 "Navy" Model, 1860 "Army" Model, and Colt Pocket Percussion revolvers, all of which saw extensive use in the American Civil War. Although American revolvers were the most common, European arms makers were making numerous revolvers by that time as well, many of which found their way into the hands of the American forces, including the single action Lefaucheux and LeMat revolver and the Beaumont–Adams and Tranter revolvers, which were early double-action weapons, in spite of being muzzle-loaders.
In 1854, Eugene Lefaucheux introduced the Lefaucheux Model 1854, the first revolver to use self-contained metallic cartridges rather than loose powder, pistol ball, and percussion caps. It is a single-action, pinfire revolver holding six rounds.