Kirst Konverter® offers a cartridge conversion cylinder for both the 1851 and the 1861 Colt Navy revolvers manufactured by Uberti or Pietta which is available in .38 Long Colt caliber, as a six shot cylinder.
The .36 caliber percussion revolver barrel has a bore diameter of .375 inches, and more important is the fact that today’s .38 caliber cartridges are loaded with .357-inch diameter bullets. Therefore, to attain accuracy with a modern .38 caliber cartridge, in your reproduction .36 caliber percussion revolver, you must shoot soft lead .38 Special, hollow base wad cutters, .38 Colt hollow base or .38 Colt healed ammunition. The soft lead hollow base bullet will “bump up” to the .375-inch bore diameter and shoot very accurately.
The chambers will actually accept .38 Special hollow base wad cutter cartridges; however the cylinder is too short and is not intended for use of the standard .38 Special cartridge. The cylinder has been made this way so that the shooter can use commercially loaded hollow base, soft lead bullet ammunition, it is not intended for the standard .38 Special cartridge.