Mitrailleuses were used in many of the major engagements of the Franco-Prussian War (1870–71), but their small numbers greatly restricted their effectiveness. Their flawed usage was a serious problem on the battlefield. While the mitrailleuses were inherently accurate, in a ballistic sense, they were often unable to zero in on targets quickly enough at great distances. Individual 25 round salvos were also too tightly grouped and lacked lateral dispersion. To make matters worse, the complex firing mechanism was vulnerable to damage at the hands of inexperienced crews. Fouling of the mechanism by black powder combustion residues and thus difficulties in closing the breech were reported as a problem after prolonged firings.