Two-blade folding pocketknife with pistol barrel, fold-down trigger and exposed hammer made during the mid- through late-19th century. Both .31 cal. percussion and .25 or .32 rimfire models are known. Percussion models have a trap door compartment to store spare lead balls, along with a ramrod and a folding scissor-style bullet mold that fit in slots in the scales like the tweezer and toothpick on a Swiss Army knife. Rare double-barrel mode is worth a premium.