The National Armory at Springfield, Massachusetts had received renown for manufacturing thousands of muskets and musketoons by 1855. But shorter shoulder arms, like carbines, had not been part of that impressive production line.
To rectify this oversight, while meeting the unique needs of dragoons and other mounted units, Springfield Armory elected to produce a hybrid percussion arm: half-pistol and half-carbine. The Model 1855 Pistol-Carbine was one of the first Springfield arms to possess the .58 caliber bore that would be standardized for later legions of rifle-muskets turned out during the American Civil War.
Capable of being fired with or without its shoulder stock, the single-shot pistol-carbine could be wielded as a pistol on horseback and deployed as a carbine on foot. To aid in continuity of fire, the novel arm employed a Maynard self-priming mechanism in its lockplate, while a flip leaf rear sight offered quick sighting for ranges out to 400 yards. While just over 4,000 pistol-carbines were to be made at Springfield Armory, the desireability of a crossover handgun/carbine was not lost on nearby inventor, Samuel Colt. Marketing variations of his six-shot Dragoon, Navy and Army revolvers fitted with similar shoulder stocks, Colt quickly eclipsed government pistol production with his repeating arms.
Two Model 1855 Pistol-Carbines reside in the collections of the National Firearms Museum. Visitors to the galleries can see an example with its Maynard priming mechanism open in case 31 and another M1855 resides in the museum's Civil War carbines display around the corner.