haha, a little soft? It sounds like someone hitting a plastic bucket with a wooden spoon. The Gustaf really needs its real life sound just because of the sheer power and fear it would bring into whomever is getting shot at with it.
I really hope you fix this and it doesn't go into the dark hole of tickets.
Video for sound reference: https://www.youtube.com/watch?v=P5SgpPjHKfE (First shot is a 20mm practice round, the rest are full 84mm projectiles)

Seem to have a similar problem, the game plays fine for up to 29 minutes and 43 seconds (Yes i timed it) then it fails and freezes.
Been trying to play wasteland with a friend but its just interrupting everything.