Simo Häyhä, also known as "The White Death," was a Finnish sniper who is credited with killing more than 500 enemy troops within 100 days during the Winter War against the Soviet Union between 1939 and 1940.
Häyhä accomplished this incredible feat with a Russian-made Mosin-Nagant M91 rifle and iron sights. He preferred the iron sights as opposed to the scope because it allowed him to shoot from a lower, less visible position. The sights also didn't fog up in the cold or glare in the sun, which could give away his position, according to Special Forces Sniper Skills by Robert Stirling.
His career ended when he was shot in the face, blowing off part of his cheek and lower jaw. He survived the shot, becoming one of Finland's most legendary heroes. He died in 2002 of natural causes.