The Philadelphia Deringer was a small percussion
handgun designed by Henry Deringer (1786–1868) and produced from 1825 through 1868. A popular
concealed carry handgun of the era, this
pocket pistol design was widely copied by competitors, sometimes down to the markings. 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 of
black powder 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 (nipple), and the gun was then loaded and ready to fire. (The half-cock notch prevented the
hammer from falling if the trigger was bumped accidentally.) Then, to fire the handgun, the 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 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, would often fire and reload daily, to decrease the chance of a misfire. Initially popular with military officers, the Deringer became widely popular among civilians who wished to own a small and easily concealable pistol for self-defense. In total, approximately 15,000 Deringer pistols were manufactured. All were single-barrel pistols with back action percussion locks, typically rifled bores, and walnut stocks. Barrel length varied from , and the hardware was commonly a copper-nickel alloy known as "
German silver". The back action lock was a later, improved design among locks, which had its spring and mechanism located behind the hammer, where it was thereby protected from dirt, fired cap residue, and gunpowder residue, unlike earlier front action locks that had their springs and mechanism located directly in the path of such residue in front of the hammer, under the tube. Because of their small size and easy availability, Deringers sometimes had the dubious reputation of being a favored tool of
assassins. The most famous Deringer used for this purpose was fired by
John Wilkes Booth who
assassinated United States President Abraham Lincoln at
Ford's Theatre in
Washington, D.C., on April 14, 1865. Booth's Deringer was unusual in that the rifling twisted counterclockwise (left-handed twist), rather than the typical clockwise twist. File:Deringer PHILADEL A.jpg|Close-up of Philadelphia Deringer's markings File:Derringer gun John Wilkes Booth used to assassinate Abraham Lincoln.) Artifact in the museum collection, National Park Service, Ford's Theatre National Historic Site, Washington, D.C LCCN2010630694.tif|Right side of the Philadelphia Deringer Booth used to assassinate Lincoln File:Derringer gun John Wilkes Booth used to assassinate Abraham Lincoln.) Artifact in the museum collection, National Park Service, Ford's Theatre National Historic Site, Washington, D.C LCCN2010630695.tif|Left side of the Philadelphia Deringer Booth used to assassinate Lincoln == Colt Deringer ==