Doushi Shoujo yo, Teki wo Ute

In 1942, as the war on the Eastern Front intensified, the normal life of Serafima, a young girl living in a rural village near Moscow, is suddenly shattered. An assault by the German forces massacred the villagers, including her mother. Just as Serafima is about to be shot, she is rescued by Irina, a female soldier of the Red Army. Determined to defeat the enemies who killed her family, Serafima, along with her comrades, undergoes rigorous training to become snipers.
(Source: HayaComic Web, translated)