The SVT-38 is a World War II-era Soviet semi-automatic rifle chambered in 7.62×54mmR, designed by Sergei Simonov in 1938.
Unlike its improved successor, the SVT-40, it is visually recognizable by its perforated metal heat shield that appears to be shorter and only covers the gas piston assembly on top.
See Danbooru post #4799665 for details.

See also

• AVS-36
• List of Weapons
• SVT-38 (Girls' Frontline)