Question: Sound trouble...

[Suhiir]

The sound override in the "Weapons" tab is most likely your culprit.
To my knowledge there is no "list" of what sound file should be associated with what weapon.

I spent hours experimenting when I rebuilt the USMC OOB and came up with a set of sounds I was fairly happy with.
However there are cases where I specifically did not assign a sound to a weapon (for example the M2/M4 Carbine) as some weapons are used to represent two (or more) different weapons, each of which has a distinct and different sound. In those cases you'll find the weapon has been assigned a sound in the "Units" tab.

The priority is:
Weapons tab
Units tab
Default (.ini file)