Legal Please read the disclaimer on the main page and note that I am not a lawyer. According to US Federal law, a muzzleloading gun is not considered to be a Title I (with certain exceptions) or Title II firearm. They are legal for most private individuals to build and own in most US states. There could be an age restriction but I don't know for sure. Note that since muzzleloaders are not subject to certain provisions of the Gun Control Act of 1968, a private citizen does not need a Federal Firearms License (FFL) to buy them by mail. There are lots of mail-order companies where individuals can legally buy muzzleloading pistol kits, rifle kits and complete muzzleloading firearms via mail-order. Note that muzzleloading pistols are almost always smoothbore s moothbore (i.e. no rifling in the barrel). Introduction One day, I had an idea to build a muzzleloading pistol. This is the result. It is a 4-shot derringer-type derringer-type of pistol. Muzzle energy is rather low so I don't think of it as a self defense device at all unless the design was scaled up a bit. It is electrically fired so there is no need to replace primers after each shot. It fires patched round balls 0.25" diameter using 4-5 grains of Pyrodex. A single CR123 lithium photo battery supplies energy to ignite the power. The ignition system is basically an electrically heated wire. Each chamber/barrel is threaded at the breech end to accept the ignitor. The battery can theoretically fire something like 20-30 shots. Its quite inconvenient to clean after shooting it. There is a 5 position rotary switch to select which chamber/barrel to fire. The first switch position is the "safe" position. After each shot, the user must manually turn the rotary switch to the next position. I have also built some test versions which are just a single barrel.
I used 1018 cold drawn steel for the receiver/barrel. The rest of the pistol is made of black Acetal/Delrin plastic and some aluminum. The pistol is about 5 inches long. I did a quick calculation of the bursting strength and peak pressure of the burning propellant so I am not worried about any blowups. In addition,
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I remotely test fired the pistol a few times and made some measurements to ensure is was safe. One of the nice things of an electrically primed pistol is that it is easy to connect some long cables and test fire it from behind cover! If I built another pistol, I'd design it with a larger grip so it could use 2 rechargeable Ni-Cd batteries. I'd also beef up the caliber but make it a 2 shot pistol. Since posting this, there have been several questions from readers. Here are the answers: q
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What is the bore size? The bore size is 0.261" (size G drill or reamer). The pistol is designed to fire 0.25" diameter patched balls. A "patch" is a piece of lubed (usually with wax/grease) cotton that is pushed down the bore by the projectile to provide a tight fit. How does the electrical priming work? I used model airplane glowplugs (the type without the heat retaining bar), pulled out the filament a bit and reinforced them with high temperature ceramic cement. One reader recommended Fox brand glowplugs for their ruggedness. The easiest way to clean the glowplug is to run a voltage through them to burn off residual materials. What is the ignition time? A bit slow - about 0.25-0.3 seconds. The CR123 lithium battery cannot supply a lot of current quickly. A typical glowplug is rated for 1.5V. It takes about 3A of current to start it glowing, then the current drops to about 2A. If I had to redesign it, I'd use one or two high rate discharge NiCd batteries instead. How long does the glowplug last? 'Don't know for sure, but I have one that has lasted 15 shots (with careful cleaning). Is there a safety? The only mechanical safety is the rotary switch set to the "off" position - so a casual brush can flip the switch to the "fire" position. As always, the user has to keep his finger off the trigger until ready to fire. It would be pretty easy to add a "grip safety" switch if desired.
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