Baby Dragoon Cartridge Conversion

This is an Armi San Marco replica of a Colt 1848 Pocket Model, known as the ‘Baby Dragoon.’ The .45 ACP cartridge is for size comparison. These guns are small!

Developed in 1846-47, the Colt Pocket Model was a .31 caliber percussion pistol based on (and financed by) the Colt Walker. It incorporated various improvements over the Walker, and these were carried over to the famous 1851 Navy, which was basically a scaled-up Pocket model.

The Pocket Model was available with or without a loading lever in a variety of barrel lengths. Despite the modest power of the .31 they were very popular, and helped set the stage for Colt’s future success. In the modern era these guns have been reproduced by most companies manufacturing percussion revolvers, and examples made by Pietta and Uberti are still available.

My gun, recently picked up as part of a trade, was made by Armi San Marco. It’s a well made gun in good condition. Of course, being me, I got it with the intention to convert it to fire metallic cartridges. But which cartridge? I’ve already done a conversion in .22, and another in .251 TCR. This time I decided I would do the classic, ‘easy’ conversion for these guns, to .32 S&W. I’ve seen modern conversion cylinders offered for this purpose, but they seem to be out of production at present.

Colt 1849 Pocket Model. This short-barreled version with no loading lever was know as the ‘Well Fargo,’ after the famous shipping company of that name.

As it happened I had a spare cylinder, so I used that for the conversion. I figured if I screwed it up I could always go back to the original. First thing was to remove the nipples from each chamber. That done I chucked it up in the vice and turned down to back of the cylinder to .650″. I then carefully bored through each chamber. each chamber needed clearance for the rim of the cartridge, so I chucked it up in the milling vice on the drill press, then used an end-mill to create room for the rim. I don’t have a .32 S&W chamber-reamer, so I used a slightly undersized drill bit, marked with tape to produce the correct depth. From there I finished the chambers with sanding drums, going up to 600 grit. Once a dropped cartridge would full seat itself in the chamber I was done with the cylinder for the moment.

Next was the breech plate. I used a piece of .262″5160 spring steel. I started by boring a 1/2″ in the piece, then using a flex-shaft tool with a carbide bur and sanding drums I enlarged the hole to fit over the .650 extension at the back of the cylinder. Next I place the cylinder on the steel and traced the outline, expanding it at the bottom to rest against the frame to prevent rotation. Using the flex-shaft with a cut-off wheel and some files I removed material to make a space for the hammer-nose. I’ll leave off the time I spent doing it over after I screwed it up the first time, and the time I spent fussing to allow the cylinder to rotate freely, but still have the bottom of the breech ring bear on the frame to prevent rotation… Then I had to relieve the rear face of the ring to accommodate the ring that stands out from the face of the breech.

The finished product- the converted, bored through cylinder and breech-plate.

After this I had to cut a loading port in the blast-shield on the frame, which I did with a large round-file and sanding drums. Once this was established I marked the breech-ring and cut a loading port in it.

The final part of the conversion was to drill the hammer-face for a fixed firing pin. I used a 3/32 drill and a piece of 3/32 music wire for the pin itself. The pin is basically a force-fit, and is glued in with Red Loctite. We will draw the curtains of charity over the extensive fussing around to get the firing pin the right length and shape to pass cleanly through the hole in the breech-plate. Similarly we will gloss over me breaking the lock/trigger return spring, and my three attempts to fabricate a functional replacement.

Here’s the hammer-mounted fixed firing pin. You can also see that I subly reshaped the squared-off rear of the trigger-guard to stop gouging my finger.

Without the loading-lever in place thought the lug under the barrel was inelegant, and decided to do something about it. Using the belt-grinder and sanding drums I re-shaped it to be similar to so-called ‘Avenging Angel’ conversion done on 1851 revolvers, except I didn’t cut the barrel shorter. It came to me with a 5-3/4″ barrel and every inch is still there.

I tested the gun with primed brass to insure everything was functioning, which worked fine.

With the gun fully functional I turned to the finish. I sanded it thoroughly with 240 grit emery cloth, removing all traces of the original finish. Sadly this included the color case-hardening on the frame. A tool had slipped and marked up the surface. I rust-blued the gun with Mark Lee Instant rust blue, which produced excellent results. The hardened surface of the frame colored slightly different than the frame, barrel and breech-ring, but I think that actually adds to the overall look of the gun.

Here’s the finished gun-

This angle shows the reshaped under-barrel lug to good advantage.
This photo shows the loading port cut into the frame and breech-ring. While there is no loading-gate the cartridges are always held in place by the breech-ring, even when the cylinder is rotated to rest the firing-pin between cartridge rims for safety. That cartridges can, theoretically, fall out of the gun is pointed sharply upwards while cocking it, but in practice this pretty much never happens..
The finished pistol shown with a 3″ K-frame S&W for size comparison.

Usually when I’ve finished a new project gun the first thing I want to do is test-fire it. Unfortunately the ranges are closed right now, and we’re all supposed to stick to home. How very annoying. OK, less annoying than getting horribly sick and maybe dying, or spreading a virus that might kill someone, but still… OK, I am a resourceful fellow, and the answer was as close as the loading bench.

I had been experimenting with swaging .32 caliber bullets, and had come up with a pretty neat 55gr. Hollow-Base Wadcutter. The very thing, I reckoned. Loaded on top of 1.0gr. of Red Dot with a Federal #100 primer it ought to be about right… and it was. The bullets had just enough power to fully embed themselves in a 1-3/4″ think kiln-dried Douglas Fir board, and as an added bonus they were remarkably quiet. Not silent, mind you, but not loud or sharp like a typical gun shot.

Five shots at five yards… not shabby. I was aiming with a 6-o’clock hold on the blue tape, and predictably for a percussion revolver it shot quite high. You can actually see the hollow bases of some of the bullets if you look closely
One the left is a bullet I recovered from the target. While you couldn’t reload it and shoot it again, there is very little distortion. On the right is the loaded ammunition.

So, pretty much a perfect Gallery Load for indoor shooting. I’ll break out the chronograph later and see what’s what. Of course I’ll be loading these much hotter for normal use (which will still not be impressive.) Load one of these hollow-base wadcutters backwards over a reasonable powder charge and this could be a very effective small-game load!

Michael Tinker Pearce, 5 April 2020


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