Now, a new release of an old classic rifle, the Kar 98K, which was widely in use in the German Military during World War II, made by DBoys and available at Gunner Airsoft.  The real steel version was "...noted for its good accuracy and effective up to 500 meters (547 yards) with iron sights. For this reason, rifles selected for being exceptionally accurate during factory tests, were also fitted with a telescopic sight as sniper rifles. Karabiner 98k sniper rifles had an effective range up to 800 meters (875 yards) when used by a skilled sniper.

The German Zeiss Zielvier 4x (ZF39) telescopic sight had bullet drop compensation in 50 m increments for ranges from 100 m up to 800 m or in some variations from 100 m up to 1000 m. There were also ZF 42, Zeiss Zielsechs 6x and other telescopic sights by various manufacturers with similar features employed on Karabiner 98k sniper rifles." (Source: Wikipedia)