Me and some of my friends don't have any shooting sounds anymore. i personally noticed it from Omega Jugg, Omega Herald, expert Deena, Ardra. Maybe its on every unit. All other sounds like the one coming up when clicking on a building, going with the cursor over "Platoons | Buildings | Gear | World Map" still working. Just not the shooting sounds of the units.
Another bug that goes in the endless list of bugs. Hope it doesnt take 5 years to fix it (or even get never fixed since over 5 years). It makes a huge difference to play with or without sounds.