Baby Dragoon Cartridge Conversion

The Colt Walker allowed Colt to rise from the ashes of his Patent Revolver Company, and in 1848 the new Colt’s first purely civilian revolver was the 1848 Pocket Model, known as the Baby Dragoon.

Colt’s 1848 Pocket Model, known as the Baby Dragoon.

This was a (nominally) .31 caliber percussion revolver built on a small frame. These were provided in a variety of barrel-lengths and could be had with or without the loading-lever mounted under the barrel. They were instantly popular, and these new revolvers and their successors in 1850 (called the 1849 Model) included mechanical improvements that formed the basis for the famous 1851 Navy and 1860 Army models.

Some of these guns were later converted to fire metallic cartridges by gunsmiths, which were typically chambered in .32 Rimfire, but to the best of my knowledge Colt never did factory conversions of these guns.

A Model 1949 Pocket Model reworked to fire .32 Rimfire by an unknown gunsmith.
Colt 1862 Pocket Navy converted to fire .38 Short Colt

Colt did produce cartridge versions of their Pocket Navy chambered in .38 Colt Short, and in modern times conversion kits for the .31-caliber reproductions were made that used the .32 S&W cartridge.

A modern reproduction of a Model 1848 Pocket Model with a .32 S&W Conversion made by Kirst.

These were not exceptionally successful because (many?) .31-caliber percussion revolvers are actually .32 caliber (.320″) and .32 S&W are actually .31-caliber (.312″) Because of course they are. This meant that .32 S&W cartridges fired through the .320 bore often didn’t stabilize well, tended to be inaccurate and produced ‘keyhole’ hits.

When I decided to do my own conversion on an anonymous Italian reproduction I modelled it on the later Colt conversions and chambered it for .32 S&W. To measure the bore I forced an oversized soft-lead slug through the bore and measured it afterwards. The bore came out, as expected, at .320″. I planned on using hollow-base wadcutters to compensate for this; the skirt of the bullet would expand to fill the bore and engage the rifling.

From here I’ll tell the story with pictures-

Here a picture of the gun prior to modification. The .45 ACP cartridge is shown for size comparison.
Here’s the finished gun. The loading lever has been removed and the barrel-lug has been re-sculpted to resemble 19thC. ‘Avenging Angel’ conversions of the 1851 Navy. The ammo shown is factory Remington ammunition.
I elected to leave the barrel full-length (5-7/8″) and left the grip alone, aside from refinishing it.
Here’s the gun broken down. The breech-ring carries a rebounding firing-pin. There is a port cut in the breech-ring for loading; there is no actual gate like there is on the larger-caliber conversions.
With the hammer at half-cock the cylinder can be rotated to load the chambers one at a time. The empties need to be extracted using a separate rod.
Here’s a close-up of the loading port. The gun can be carried with all five chambers loaded by resting the firing-pin between the case-heads.
Normally the rear sight would be located on the hammer-nose, but since I used a breech-ring with a rebounding firing-pin I had to cut that away. Instead I mounted the rear sight on the barrel just ahead of the forcing-cone. This gives a good 5-1/2″ of sight radius, and since the sights can’t move in relation to the barrel accuracy should be pretty good.
The casing is so short the semi-wadcutter cannot be seated to full depth. These bullets are Hornady 90gr. HBWCs. These are loaded over 1.2gr. of Unique.
Unexpectedly all the bullets showed some expansion when fired into Clear Ballistics 10% ordinance gel. The bullets expanded to .320, with expansion at the tip was to an average of .360. That’s not much, but it’s more than I expected.
As you can see the bullet expanded enough to fully engage the rifling.

I fired five shots over the chronograph and into the ballistic gel. They averaged 769 fps. and 118 ft./lbs at the muzzle, with an extreme spread of 36 fps. The bullets all penetrated very close to 13-1/2″ into the gel. I didn’t fire them through denim because, uh… I forgot to.

I’ll need to take it to the range for a good workout, but I’m pretty pleased with how it’s working out. I am going to mount the breech-ring on the breech with screws; very occasionally the breech-ring will move enough to momentarily bind the action.

The gun needed holster, of course. I modelled mine on the simple ‘gun-bucket’ style popular in the 1870s.

The holster is made from 7-8 oz. top-grain vegetable-tanned tooling leather. It’s double-needle stitched with #7 linen cord.
The belt-loop on the back is located to to hold the butt away from the hip for an easy draw.
Here’s the gun shown with an 1860 Army for size comparison.

Addenda

This morning I fired the Remington Factory ammo into the gel. The bullet penetrated 10-1/2″ and wound up nose-forward. As you can see the rifling grooves are quite deep and plain. When measured the bullet had ‘bumped up’ to .320″. Apparently the very soft lead bullet works just fine, at least in the modified forcing cone of this gun. I’ll take it to the range and run some more rounds through it.

Michael Tinker Pearce, 28 January 2021

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