I’d imagine that clearing out buildings in the brutal fighting on the eastern front would have been a lot easier with a shotgun. We’re any Soviet troops issued shotguns or were they ever used by red army troops?
Shotguns were not issued to Red Army troops. Official instructions for urban combat suggested the liberal use of grenades and submachine guns.
It would be possible for shotguns to see some use in partisan units, where civilian hunting weapons could be used in battle. However, the Partisan's Companion, an official manual for partisan warfare distributed by the Soviet government, makes no mention of the operation of shotguns, only the TOZ-8 and TOZ-9 sport rifles.
Sources:
http://www.tankarchives.ca/2017/12/partisans-companion-weapons-of-combat.html