The battlefield use of the mitrailleuse as artillery was a fatally flawed concept. To avoid being hit by Dreyse rifle fire, the mitrailleuse batteries were systematically deployed beyond about 1,400 m (1,500 yards) from the Prussian lines. Although the maximum range of the mitrailleuses was 3,400 m (3,700 yards), the distances at which they were typically engaged rarely exceeded 2,000 m (2100 yards) which was less than the reach of French field artillery. However accurate fire at 1500 yards was always extremely difficult to achieve with the typical open sights present on the mitrailleuse. For instance, mitrailleuse bullet impacts on the ground could not be observed in the far distance unless enemy ranks had been disrupted by hits from them. It may be noted that modern machine guns are typically used at ranges far shorter than their maximum range—the M60 machine gun, for instance, is normally used at an effective range of 1,100 m (1,200 yards), compared to its maximum range of 3,725 m (4,074 yards). The mitrailleuse, by contrast, was often used at the outer edges of its range and without the benefit of optical range finding equipment. These deficiencies in the operational usage of the Reffye mitrailleuse proved disastrous in the Franco-Prussian War.