The Venerable .31 Caliber
Vest Pocket Derringer
CVA vest pocket derringer by Armi San Marco, Italy
Learn All About Shooting A Replica
.31 Caliber Black Powder Pistol
by Timothy P. Banse
In modern parlance the term derringer, a generic misspelling of the last name of Henry Deringer, means an easily concealable, smallest usable handgun of a given caliber. In other words, a generic term for a small back-up pistols meant to be a last resort weapon kept out of sight.
In American culture the name Derringer conjures up the image of hold out guns, card sharps and Mississippi Riverboat gamblers. Recently, at a gunshow, I spied a kit gun in a box: A CVA Vest Pocket Derringer. Built in Italy at Armi San Marco, these replica black powder muzzle loaders were imported into the United States back in the 70s, by Connecticut Valley Arms, Inc of Norcross, Georgia. The Italian manufacturer ASM was sold and nowadays the pistol is made by Ardesa and imported to the USA by Traditions Firearms of Old Saybrook, Connecticut. The current rendition by Traditions is basically identical to the CVA model, save the formerly walnut grips have been replaced by simulated ivory and instead of rough, the brass receiver/barrel is highly polished to a lustrous finish. In a word, the Traditions derringer is beautiful whereas the old CVA was a plain Jane. Also the current iteration is fully assembled and is not available in kit form.
Vest pocket derringer by Ardesa
Photo courtesy of TraditionsFirearms.com
As for the gunshow CVA kit, still resplendent in its original box, it had already been assembled, albeit poorly. The brass remained unpolished, the grips still rough. So naturally I bought the firearm. After some final fit and finish with Emery cloth and steel wool, I took it to the firing range and test fired it.
| Vest Pocket Derringer | Specifications: |
|---|---|
| Caliber | .31 Smoothbore |
| Ignition | Percussion - #11 caps |
| Barrel | Smooth bore .310 id .625 od |
| Powder Charge | No patch 5 to 10-grains FFFG 9-grains recommended |
| Projectile | .320 pure lead round ball
45-grains |
| Construction | Brass receiver/round barrel |
| Length Overall | 4.75 inches |
| Weight | 12-Ounces |
| Barrel Dimensions | 2 3/8 inches Overall .625 od |
| Hammer | Color case-hardened |
| Grips (Bird's Head) | CVA - Wood Traditions - Simulated Ivory |
| Sight | Front bead |
Loading and Firing the Vest Pocket Derringer
To load this weapon of mass destruction bring the hammer back to half-cock, which allows opening the breech and exposes the nipple. With the hammer down, the firing pin locks the action shut. (It's not a safety, because with the hammer resting on a live percussion cap, it could not be declared safe.) Swing the breech end of the barrel to the right, opening it wide and exposing the percussion cap nipple. Place a # 11 percussion cap on the nipple. Swing the action closed. Draw the hammer back to full-cock. Fire a sacrificial percussion cap (#11) to clear the nipple's fire channel. Pop!
Close the action. Rest the hammer against the nipple to lock it. Charge the piece with propellant. More specifically, from five- to ten-grains of FFFg Black Powder, with eight-grains being the recommended charge. With a ramrod, tamp the black powder charge deeply into the barrel to make sure there are no air gaps. The brass ramrod that screws into the underside of the barrel is a joke. You'll need to either buy one or make your own from a hickory dowel.
Charge the Vest Pocket Derringer with 5- to ten-grains of a fast burning FFFG Black Powder, such as Goex or Swiss.
Insert an appropriately-sized round ball into the muzzle, tamp deeply into the bore, snug against the powder charge. No patch is required. Restated for emphasis" Do NOT use a patch. TIP: It helps to engrave witness marks on the ramrod shank so that when inserted into the barrel, the marks reveal whether the round ball has been seated deeply enough against the powder charge.
Powder charge and round ball loaded, once again swing the breech end of the barrel to the right, exposing the percussion cap nipple. In the old days they were called cones. As mentioned earlier, this one takes a #11 nipple.
Capped and loaded, swing the breech closed. Keep the muzzle pointed down range. Line up your target with the front bead sight. There is no rear sight. Trigger pull is stiff. Squeeze the trigger. Bang! Recoil is minimal. Its report is louder than one expects with a pistol of this size. You'll need earplugs or muffs if you value your upper range hearing.
The Derringer barrel is not rifled, so naturally it follows accuracy is hardly stellar. Though, it's not bad up to five- or ten-yards. With 500-feet per second muzzle velocity and lightweight bullet (45-grains) knock down power is minimal: About 40 ft/lbs energy at the muzzle. So how does this short barrel .31 compare to the .25 ACP?
| Ballistic Comparison | .25 ACP | .31 Percussion | .22 Short | .22 Long Rifle |
|---|---|---|---|---|
| Bullet Type | JHP | Round ball | Round Nose | Lead solid |
| Bullet Weight (Grains) | 45 | 45 | 27 | 40 |
| Muzzle Velocity (Fps) | 815 | 525 | 800 | 850 |
| Muzzle Energy (Ft Pounds) | 66 | 26 | 87 | 131 |
Both .22 Short and Long Rifle ballistics were derived from longer rifle barrels, while .31 and .25 ACP ballistics are from pistol barrels.
.31 Percussion Ballistics and Knock Down Power
When comparing Vest Pocket Derringer ballistics to modern ammunition the .31 falls dramatically short of the performance of either a .22 Short or a .25 ACP, let alone the more potent .22 Long Rifle and .32 ACP rounds. For plinking, the Vest Pocket Derringer is fun. However, if you have actual self-defense in mind, the answer is obvious, as we will soon discuss.
Simply put, back in the day the strategy of opening fire with a mere Derringer was to cause enough damage to injure a bad actor enough to hamper his ability to continue the fight. This is similar to the strategy fielded in a fistfight, of intentionally breaking the other guy's nose so as to end the fisticuffs early. In a gunfight, even a .31 round ball shot into the center of mass would do that, but not necessarily for the reason you would think. Consider how back in the day, before the advent of X-rays and antibiotics, even a superficial wound could kill a man, sometimes only after long agonizing number of days to be endured in excruciating pain. Suffice it to say the prospect of taking a round from a black powder pistol, no matter whether a .44 or .31 caliber, was a detriment. So as it came to pass, back in the 18th century, brandishing a .31 caliber pocket gun was often enough of a threat to ward off street punks or asshole dogs. Thugs didn't want to get shot in the face anymore back then than they do today on the streets of New York or Los Angeles.
Cast Versus Swaged .310 Projectiles
As we previously mentioned in the text herein above, the Vest Pocket Derringer fires .310 diameter projectiles. With that thought in mind, one might reasonably ask what are the options? First, and most obvious, are store-bought round balls packaged in boxes of 100. Hornady makes .32 Cal .310 Lead (pure) Balls, and they are also readily available, as are round balls, conicals and sabots in the most popular black powder calibers.
Hornady Muzzle loading projectiles are cold-swaged from pure, soft lead, a process which eliminates air pockets and voids, that otherwise commonly plague cast projectiles. Because Hornady round balls are swaged, as opposed to cast, there is no sprue. Each ball is perfectly symmetrical, sans shrinkage, sans wrinkles. Being smoother and rounder lends better rotation in flight.
The second worthy option is to Do-It-Yourself, to cast round balls on your work bench. To that end, Lee Precision's Double Cavity .311 mold throws a 45-grain round ball. But wait a minute, the Derringer's spec is .310, not .311! Will the .001 of an inch make difference? The short answer is no, it won't. The mold includes handles, but requires a lead pot and dipper to get into operation.
As for the mold proper, Lee Precision's design kicks out a round ball replete with a sprue. But because of a tangential cut off, the nib at the sprue is minimal. That said some naysayers claim that because of the sprue, the ball is not a complete sphere, that it's nothing more than an imperfect sphere marred by a flat spot. Because of that imperfection, some charcoal burners advise purchasing a box of swaged balls. For perfectionists, Okay. Fine. On the other hand, you won't be shooting a Vest Pockete Derringer at Camp Perry shooting competitions. In at least this appllicaiton the minimal loss of accuracy due to a sprue is rendered moot.
More to the point, Lee Precision offers a quality bullet mold at an affordable price. Lee machines its mold blocks from aluminum, making them effectively rust-free. Also salient, aluminum molds heat up and cool down more rapidly than do iron or steel molds. As a result, flawless bullets, sans wrinkles, can be produced only after a few casts. Moreover, aluminum blocks are one-third the weight of iron or steel mold blocks which pays dividends by way of lessened fatigue during long casting sessions.
Personally, I shoot both Hornady .310's, and round balls dutifully cast with a Lee Precision Mold. On paper targets the gun doesn't know the difference between swaged and cast. At least so long as when loading the gun I carefully center the sprue on top of the cast ball before jamming it down the bore. In other words, on loading, the ramrod pushes directly against the sprue.
Beyond swaged and cast round balls, there is a worthy third choice: Namely buckshot. Cast on a home workbench, or bought in five pound bags, No.1 buckshot; measures a .30 to .31 thousandth of an inc, depending on who makes it. Which brings up the salient point, when casting round balls, or loading buckshot, keep in mind pure, soft lead is what called. The logic is as simple as the sea is salt. Pure lead, balls or conical bullets, are soft enough to load into the cylinders of a cap and ball revolver and when fired, be engraved by the rifling and be set to spinning down range all the way to the target. So how can you tell whether a lead ball is soft enough? Simple. If you can dent it with a thumbnail, it's considered soft enough.
Accoutrement: Loading blocks, Capper, Powder flask/measure, Nipple picks. Photo courtesy CrazyCrow.com Trading Post
The Vest Pocket Derringer comes without accessories, save for the worthless brass ramrod that screws-in beneath the barrel. You'll need to fashion a ramod out of a hardwood dowel (hickory), with an outside diameter narrower than .320 of an inch so as to fit inside the muzzle. Eventually you'll want a nipple wrench. Preferably one with an integral nipple pick to clear the firing channel of any debris that may have accumulated. A powder charge measure with a spout small enough to fit inside the muzzle means no spilled propellant. A loading block makes it easy to reload with the annoyance of loose balls rattling around in your pocket.
Finally, the replica Vest Pocket Derringer is fun to shoot, to stick in a display case, or to give as a present to an aficionado. Have your wife read this article.
Schematic drawing of the vest pocket derringer
| Parts | |||
|---|---|---|---|
| A. | Frame | J. | Right birds head grip |
| B. | Barrel | K. | Left birds head grip |
| C. | Barrel detent retaining screw | L. | Grip screws (2) |
| D. | Barrel detent | M. | Trigger |
| E. | Barrel detent spring | N. | Trigger spring |
| F. | Nipple | O. | Barrel locking screw |
| G. | Hammer | P. | Mainspring |
| H. | Hammer Screw | Q. | Ramrod |
| I. | Trigger Screw | R. | Front sight bead |