This is Simo Häyhä, the deadliest sniper in world history with over 500 confirmed kills in less than 100 days. He used no scope on his rifle and once held off over 4,000 Soviets with only 31 other Finns.
Over the course of the Winter War, which lasted roughly 100 days, Häyhä killed between 500 and 542 Russian soldiers, all with his antiquated rifle.
While his comrades were using state-of-the-art telescopic lenses to zoom in on their targets, Häyhä was fighting with an iron sight, which he felt gave him a more precise target.