Yes, you can reduce the volume of music in game settings. The problem is, that in the audio settings, ,,game volume'' slider is responsible for weapons' sounds and voices, even though in the voice settings there is ,,voice receive volume'' slider. So if you want to reduce the volume of weapons' sounds, it will reduce the volume of voices as well, which is useless and the ,,voice receive volume'' slider doesn't make sense. Of course you can completely remove weapons' sounds (all, except yours) via server settings, but this is not a good solution for me.