The 13 mm centerfire Reffye mitrailleuse cartridges were loaded into interchangeable steel breech blocks, unlike the Montigny mitrailleuse, whose ammunition was held by the cartridge base in plates. When firing the mitrailleuse, three breech blocks were kept in continuous use: one being fired, one being pressed down on the extractor and one being loaded from a single pre-packaged 25-round box. Adjusting the elevation of the mitrailleuse in accordance to the distance to the designated target was performed with an elevating screw identical to that on a regular artillery piece. The mitrailleuse's barrel could also be moved sideways while firing, to the right and left, in order to adjust for range and provide lateral sweeping fire if needed. The lateral sweep was narrow, however, thus most effective at far distances only. The weapon's field of fire was so narrow that Prussian soldiers were often hit by several bullets at once. During an early engagement of the Franco-Prussian War, at Forbach in Alsace on August 6, 1870, a Prussian general officer (General Bruno von François) was brought down by a very closely spaced volley of four bullets. According to the Prussian regimental record, those four mitrailleuse bullets had been fired from 600 meters away. French artillery attempted to rectify this problem by developing special ammunition capable of firing three bullets from the same cartridge for short-range point-defence.