The first step in cutting a loading port is to mark out exactly where the recoil shield must be cut back in order to fit a cartridge into the gun. I did this by placing the gun into the half-cock position and placing two pieces of masking tape in parallel to extend the line of the chamber across the recoil shield.
Figure 1 shows the tape in place that marks the location where the loading gate will be cut. The next step was to paint machinist layout fluid on the recoil shield as a guide for removing metal. The tape was removed and I started filing with a rattail file.
The going was slow with the file so I switched to a die grinder with a carbide cutter. A die grinder is similar to a Dremel tool, but much larger and more powerful. Mine has a standard industrial size 1/4 inch collet and removes metal very quickly.
It is easy for a die grinder to get away from the user so it is important that the frame of the gun be securely clamped to the bench and that I brace my hands in a way that I maintain good control over the grinder. I may have to see about buying a ball end mill cutter for future projects.
After making the initial cuts, I found it easier to remove the bluing by using Navel Jelly to take the frame down to bare metal. This was done by painting the solution onto the blued frame, letting it dissolve the bluing, and then rinsing it with water. Once that was done, I painted the area again with layout fluid so I could make marks in the blue dye to guide my cutting.
I found it necessary to rough out the area with the die grinder and to alternate to using the round file. I recommend using duct tape to cover any exposed parts of the frame in case the file slips. I let the file slip a few times and it gouged the arbor. This will not be a problem, but it is better to avoid doing any more damage.
Figure 2 illustrates the completed cut through the recoil shield. I used an empty .45 cartridge to constantly check the dimensions and clearance as I worked. The blue layout fluid can be clearly seen in this photograph.
I changed to the smaller Dremel grinder and used a padded sanding drum as I approached the final dimensions. My final sanding was done with a .44 magnum cartridge casing wrapped with sandpaper.
Figure 3 shows the loading port with the cylinder and backing plate in place and is ready for test firing. Yes, those are live primers in there being tested to make sure there is sufficient clearance.
WARNING, the conversion of a cap and ball revolver will to cartridge does not give it sufficient strength to use any smokeless cartridge or any load that approaches the chamber pressure of the original charge. Metal has been removed from the cylinder so it is a little weaker than the original chamber.
I took eight .45 Colt cartridges and loaded them each with 30 grains of Clean Shot as measured by volume. This quantity fills the case and will allow about an eighth of an inch of compression. The barrel of this gun was designed for soft lead balls so I loaded a .451 round ball in each cartridge and crimped the casings into the lead. This provides an acceptable load that simulates the C&B load with the ease of metallic cartridges.
Photo by Oaktown Rider
It was finally time to test the gun to see how it fires. I had concerns about the loose clearance between the bullet and the chamber as the bullet moves toward the forcing cone. It turned out to not be a problem. I wore a heavy coat and gloves for the first shot and looked away as I pulled the trigger.
The gun felt very good and most recoil was absorbed by the weight of the gun. I loaded five cartridges and Figure 4 shows the third of a string of five shots that smoked, boomed, and made clanging sounds as the lead ball hit the steel targets. These photos were taken by the Oaktown Rider after a CAS match on a rainy March afternoon in Manteca, CA.
It always feels good to shoot a conversion for the first time and I was excited by the results of this trip to the range. It was now time to start making a loading gate, to screw the backing plate to the standing breech, to start thinking about repairs to the loading arm assembly, and to start thinking about how to make an empty cartridge extractor.
The loading gate began with a heavy piece of steel that was laying on my bench. I began by applying layout dye on the steel and marking it with a scribe. Figure 5 shows the piece of steel before any cutting or filing was done.
After laying out the new loading port on the plate of steel, I put it in to my vise and cut out the marked area. I then started shaping the part down to the cutout lines with a rough-cut file. It was more expedient to also use a bench grinder to remove much of the excess material around the edges.
The bench grinder made quick work of the excess steel in the part. Figure 6 shows the grinding process and you can see I am using pliers to protect myself from the heat generated by the friction of the grinding wheel against the steel. A close inspection of the grinding photo shows the short yellow sparks with many spurs that indicate I am grinding on a high-carbon steel.
Using a bench grinder was was rather quick, but such a small part heated up very quickly. As I ground the part to the proper shape, I had to often stop and allow the part to cool.
I then clamped it in the vise and began recessing the material to fit the contours of the backing plate.
This is a slow and tedious process of fitting, filing, dying, marking, and filing again.
The part began to fit into place, but needed to be further contoured around small spots where it would bind and around other where it was hitting high spots. I was finally able to fit the part so it went through a full range of motions while closing to an acceptable fit. I want this to continue to look like a conversion so I don't want the parts to be fit perfectly.
Figures 8 and 9 illustrate how the basic loading gate is beginning to properly fit into the backing ring, but it still needs to have the center ground out with a Dremel tool. The part was then worked with a rattail file and ground with a sanding drum in the Dremel. I used an abrasive disk on the Dremel to get into small areas and quickly remove metal. I felt a little like a dentist trying to fit a crown on a tooth.
I used the Dremel tool with an abrasive disk to match the shape of the ring to the existing contours of the backing plate while creating a more pleasing radius. The extra work will make the job look much more professional.
I used a block of steel that was too thick to allow me to construct a little catch to grab with a thumbnail. I used the Dremel with an abrasive disk to recess the underside of the thumb catch, but stopped before completing the work. The notch is there, but will be finished when I move to the final finishing stage of the project. I want to spend a little more time studying various notches before completing the work.
Figures 10 and 11 show the new loading port sitting in the gun and ready for the next stage of construction. The port opens smoothly and is held in place by a leaf spring in either the open or closed position.
The loading gate for this gun required at least ten hours of cutting, filing, and fitting. It required far more time than I had anticipated and the going was slow.
I am fairly new at metalworking so I am still learning a few techniques. Stay tuned on this project because next month I plan to add the cartridge extractor assembly to finish off the basics of this conversion. After that, it will be time to do the final finishing, which is intended to be a nickel plating job done right in my home shop using a Caswell plating kit.
Here is a little tip for those of us who need to do a lot of filing on various metals. Files become clogged with little bits of metals and need to be carded with a stiff brush. Professionals use a special chalk to fill the teeth of the file and prevent these pieces from become imbedded. I have found that keeping a little old gypsum wallboard around and filing it to fill the file will help prevent clogging of the file.