Kerr's Patent Revolver - Operation

Operation

The Kerr Revolver featured a side-mounted hammer on a back-action lockplate. Unlike other revolvers of the day, the lock mechanism of the Kerr revolver was identical to that of back-action rifle and single shot pistol percussion locks of the time. The simple action was designed to be easily repairable in the field without requiring model-specific spare parts. The Kerr had a top strap over the cylinder, which is held in place by a pin that runs into the back of the frame below the hammer. The pistol is 12.25 inches overall with a barrel length of about 5 inches. Nearly all were made in .44, or "54 bore", caliber; a few in the smaller .36 caliber.

The Kerr is often described as a double action revolver. That is true as to only the earliest Kerrs produced, but all the later production were of the simpler single action mechanism. With this simpler single action type, the hammer must be manually pulled back until it locks in the full cock position. This cocking action causes the cylinder to revolve, thus bringing a fresh chamber into line with the barrel. Once the hammer has been cocked and locked back, the user must pull the trigger to cause the hammer to fall, striking the percussion cap over the chamber and firing the weapon. If the hammer is left down, and the trigger is pulled back, the cylinder will revolve, but the hammer will not be cocked back, as would be the case with true double action revolver. The term "single action" means that the pulling of the trigger has only one effect—it releases the cocked hammer. In a "double action" revolver, the pulling of the trigger has two effects—it caused the hammer to cock back, and then as the trigger pull is continued, it releases the hammer. The double action mechanism in the early Kerrs was more complicated to manufacture and to keep in good adjustment and repair, and was early on dropped in favor of the simpler single action mechanism.

The London Armoury Company manufactured Kerrs have engraved on the side of the frame "KERRS PATENT No. xxxx" with the xxxx representing a number. This is the serial number of the gun, and not the patent number. This serial number is also on the side of the cylinder. Mistaking this serial number for a patent number is an error often repeated from Edwards,Civil War Guns, by many writers. This same serial numbering convention used on the Kerr was used on the Adams Revolver (made by the London Armoury Company, among others), and also is seen on Samuel Colt's percussion revolvers of all models, where the serial number of each revolver (stamped on various places on the Colt revolver) was stamped on the cylinder following the words "COLTS PATENT No. " On the Kerr Revolvers, as with the Adams and Colts, these numbers are sequential and are serial numbers and not the patent number.