Transitional Pistols
Transitional Pistols occupy the unusual middle ground between Pepperbox pistols and the full developed frame revolver. The above Transitional Pistol is an English example. It combines the cylinder mechanism of a Pepperbox Pistol with a single barrel. Where as almost all Pepperboxes were smooth-bored Transitional Pistols often had rifled barrels. However they were fundamentally weak the cylinder and barrel are attached to the pistol body only via the axis pin which was prone to damage or breakage if the pistol was treated roughly. The second major drawback to many of these pistols is that they operate by much the same firing mechanism as a Pepperbox with individually placed percussion caps placed at right angles to the cylinder this, as in the older pistols, led to misfires.
Transitional pistols were popular throughout the first half of the 19th century between the 1830s through to the 1860s. Examples often found themselves onto American Civil War battles during the early phases of the war but they were certainly obsolete by the point with Remington and Colt pistols being far better designed with solid frames.
Image Source