HENRY DERINGER'S SINGLE-SHOT POCKET PISTOL: This pistol was a popular choice for some pioneers traveling to the gold fields of California. This “derringer” incorporates one handy feature – a capbox fitted into the bottom of the pistol, allowing spare percussion caps to be on hand when needed. While sold as a single handgun or in pairs, some purchasers had local gunsmith load their firearm for them, trusting that they might only need the one shot in the future.