Early Colt revolvers operated from what was known as an "open frame" design meaning that there was no supporting structure set over the revolving cylinder, making them less robust than the competing Remington revolvers. All that changed with Colt's newest handgun - the Model 1855 - which was designed by Samuel Colt himself and developed by Colt employee Elijah Root. Hence the revolver came to be known under several nicknames including "Root Revolver" and "Root Model Revolver". These guns stemmed from the Colt Patent Firearms Manufacturing Company out of Hartford, Connecticut.
Key to the design of the Model 1855 was the encased five-shot cylinder whose frame ran above and beneath it for a more sturdy gun. The cylinder was either smooth-sided or fluted depending on the product and set above and ahead of an ergonomic, wood covered curved pistol grip. Additionally, some Model 1855s were sold with engraved cylinders showcasing typical anti-Indian sentiment or stagecoach holdup scenes consistent with the times. The trigger was of a stud-trigger type with a single-action lock and finished sans a trigger ring. One major notable item of the Model 1855 design was its use of a side-mounted hammer which was set to the left side of the gun body, hinged by a screw along the right side. The hammer sported a very noticeable spur design, nearly vertical. A visible screw held the cylinder pin in place through the rear of the gun. The barrel - available in varying lengths - was naturally fitted ahead of the receiver.
The Model 1855 was offered in barrel lengths to include 3.5, 4 and 4.5 inch assemblies. It also came in .28 and .31 caliber forms which made the revolvers relatively easy to handle and fire but were soon found to be lacking in their man-stopping qualities. The Model 1855 utilized a percussion-based firing system that involved loose gun powder, percussion caps, bullets and paper-based cartridges - otherwise known as "Cap and Ball". Bullets weighed 47 grains with a 12 grain powder charge, sporting a muzzle velocity of 750 feet per second.