In 1855, Prussian customs officials discovered a shipment of 3,000 Colt 1851 Navy model revolvers (and their accouterments) hidden in bales of cotton being shipped from New York to Russia. Prussia was a neutral power in the ongoing Crimean War, but had prohibited transit of arms across its borders. Squeezed by a British blockade of its ports in the Baltic, Russia tried to being in these pistols through Prussia anyway, and was caught (much to the embarrassment of Colt, who was trying to sells his revolvers to the British at the same time).
After three years of stalling, the Prussian government decided to keep 1,000 of the revolvers for issue to its own navy, and sell the remaining 2,000 at auction. The navy revolvers and their accessories (powder flasks and cappers) were stamped with “KM” (Königliche Marine, or Royal Navy) and sequential inventory numbers. They would be the first repeating pistols issued to the Prussian Navy.