The Philadelphia Deringer is a small percussion handgun designed by Henry Deringer and produced from 1852 through 1868. The term derringer is actually a misspelling of the maker’s last name. Kind of like kleenex (with a small k), or “xerox,” the term derringer is now used to describe any pocket-sized pistol.
The original Deringer pistol was a single-shot muzzle-loading pistol. That means you had one ball of lead backed by the power of a measure of black powder. No multi-shot shootouts with this little beauty. Subsequent models were made to use the new cartridge type ammunition–aka a bullet–but a derringer never held more than two shots.
Derringer often refers to the smallest usable handgun of a given caliber. They were frequently used by women, because the size made the pistol easy to conceal in a reticule on slipped into a stocking garter. Derringers are not repeating firearms. The original cartridge derringers held only a single round, usually a .40 caliber cartridge. [.40 refers to the diameter of the bullet, in this case .40” or 10.16mm.] The barrel pivoted sideways on the frame for reloading.
The famous Remington derringer, sold from 1866 to 1935, was designed with a second barrel on top of the first. This meant two shots instead of one, without much more weight to carry around. On this two-shot pistol, the barrels pivoted upward for reloading.
If you plan to use this pretty little thing for personal protection, keep in mind that the bullet moved very slowly–about half the speed of a modern bullet. It could actually be seen in flight. Still, at close range, such as at card table or in a stage coach, it could be deadly.
Another thing to consider, should you want a character to carry a derringer: it took a lot to load and prepare the pistol. I’ll let you read for yourself.
“For loading a Philadelphia Deringer, one would typically fire a couple of percussion caps on the handgun, to dry out any residual moisture contained in the tube or at the base of the barrel, to prevent a subsequent misfire. One would then remove the remains of the last fired percussion cap and place the handgun on its half-cock notch, pour 15 to 25 grains of blackpowder down the barrel, followed by ramming a patched lead ball down onto the powder, being very careful to leave no air gap between the patched ball and the powder, to prevent the handgun from exploding when used. (The purpose of the patch on the ball was to keep the ball firmly lodged against the powder, to avoid creating what was called a “short start” when the ball was dislodged from being firmly against the powder.) A new percussion cap would then be placed on the tube (what today would be called a nipple), and the gun was then loaded and ready to fire. (The half-cock notch prevented the hammer from falling if the trigger were bumped accidentally while carrying the handgun in one’s coat pocket.) Then, to fire the handgun, a user would fully cock the hammer, aim, and squeeze the trigger. Upon a misfire, the user could fully re-cock the hammer, and attempt to fire the handgun once more, or, equally common, switch to a second Deringer. Accuracy was highly variable; although front sights were common, rear sights were less common, and some Philadelphia Deringers had no sights at all, being intended for point and shoot use instead of aim and shoot, across Poker-table distances. Professional gamblers, and others who carried regularly, often would fire and reload daily, to decrease the chance of a misfire upon needing to use a Philadelphia Deringer.” http://en.wikipedia.org/w/index.php?title=Derringer&action=edit§ion=3
And do you know how this gun changed history? It was the weapon used by John Wilkes Booth to assassinate President Abraham Lincoln in the Ford Theater on April 14, 1865.