Sometimes shots can't be heard even if the shooter is less than 100m of you. I don't know if this only affects the Moisin 9130, i can just confirm 100% sure this bug only with that rifle.
I don't know if the enviroment is the reason (e.g a treeline blocking the sound). But sometimes anything is heard even if the shooter makes multiple shots.
This is an important issue that should be reviewed. If i get more information i will upload it as fast as i can.