Conversion Cylinders

Conversion cylinders area modification for blackpowder cap and ball revolvers to take metallic cartridges. The typical conversion cylinder may be a five or six chamber cylinder designed to fit a Pietta, Uberti, or Ruger Old Army revolver that is specific to the handgun. As an example, Taylors & Company (TaylorsFirearms.com, lists seven different cylinders for Pietta and Uberti handguns. A Pietta cylinder doesn’t fit a Uberti and even with the correct cylinder, some fitting may be needed.

Conversion cylinders are designed to accommodate firing modern cartridges such as 38 Smith & Wesson or 45 Colt, depending on the conversion cylinder. A cap and ball revolver with an original caliber of .36 takes a 38 Special conversion while .44 caliber guns take a 45 Colt conversion cylinder. They are of strong steel and quite safe but common sense tells us that brass frame cap and ball revolver may 44 caliber black powder cap and ball cylinder, left, compared to the five-shot 45 Colt cartridge cylinder, right.

It is a neat trick to design a five-shot cylinder that works simply by sliding it onto the revolver’s arbor. not stand up as well in long use as steel frame revolvers. Fortunately, the strength is in the cylinder, although small parts and the frame may take a beating. In every case conversion cylinders are limited to standard pressure loads. +Por heavy loads would be a real problem and should be discouraged. A standard loading such as the Black Hills Ammunition cowboy loads are recommended.

The cylinders normally do not require fitting if they have been ordered correctly for a specific To the right is the original .44 caliber cap and ball cylinder. In the lower part of the photo the firing pin plate for the conversion cylinder is illustrated. firearm. Just the same, when it is considered that thousands of these revolvers have been manufactured over a span of decades, we may find some fitting is needed.

The cylinders are installed by removing the old cap and ball cylinder and replacing it with a conversion cylinder. The conversion cylinder is a machined unit with standard cylinders like most revolver cylinders. The firing pin, however, is a special design. A backplate lines up on a single pin on the rear of the cylinder. This backplate contains five or six firing pins, one for each cartridge. The hammer, normally designed to crack a percussion cap, now falls on a floating firing pin.

This is a novel system that works well. To unload the cartridge conversion cylinder, remove the conversion cylinder from the handgun, then the back plate, and then the cases shoved or shaken out. While not a fast system, it is simple and reliable.

Pretty interesting design and very well machined. I found it interesting that the six-shot Colt 1860 Army takes a five-shot 45 Colt cylinder. Since the Colt Army uses a rebated cylinder similar in diameter at the rear to the .36 caliber Colt Navy revolver, a six-shot cylinder was out of the question. Yet, the lockwork operates just fine with the five-shot conversion cylinder in place. Cylinder Fixes All revolvers based on the Colt Single Action Army operate on the same principle.

The hammer is cocked and moved to the rear, locking in place until the trigger is pressed. A stud on the hammer will contact the rear of the cylinder bolt as the revolver is cocked. The cylinder locking bolt then drops downward and the cylinder is allowed to rotate. As the hammer continues its travel past the half cock position/half cock notch, the bolt is released and the bolt spring presses the bolt stop into position and the cylinder is locked tight.

When the trigger is pressed the hammer falls and the revolver fires. The cylinder must remain locked in place for accuracy, reliability, and safety. I think that a problem with many shooters is that they do not pull the hammer completely to the rear before lowering the hammer. If the hammer is brought only to the half cock notch the system doesn’t properly operate. This also leads to the often-noted scoring of the cylinder by the bolt stop. Occasionally there are difficulties with conversion cylinders.

They are not big problems but must be addressed based on standard cylinder fitting techniques. One such difficulty came into my shop recently. The shooter had taken good notes on his problems, making the initial assessment much easier. He reported the ratchets on the conversion cylinder were different than the original cylinder. I agreed, but they seemed a proper fit. What I found was that the hand in the revolver was just slightly too long to properly mate with the new conversion cylinder.

The result is a different angle or fulcrum. The old cylinder worked fine, but the new cylinder, when engaged as the shooter lowered the hammer without firing, wanted to move in the opposite direction than the normal rotation of the cylinder. There were several avenues to pursue toward a fix. If the hand was left as-is it would work fine with the original cylinder and mostly okay with the new one with a lessthan-ideal fit.

If the new cylinder was intended to be the normal go-to cylinder I could modify the ratchets slightly to work with both. That seemed the preferred course, having two cylinders matched to the revolver. Another course could be to file the hand very slightly shorter. Of course, this demands careful work as very little effort will shorten the Far