Open up the gunspecs and comment out any sounds past
sound4.
You may also need to to coment out any sound frames past 4 as well. If this causes you to loose important sounds like reloading or cocking. You will have to choose which sounds to sacrifice and edit the gunspecs accordingly (like dryfire, putaway or retrieve).
Hope that helps.
Edit: Please back up your originals and note this advice is not from first hand knowledge, only from what users have told me and what I know tends to happen in source mods, in general, with those packs.
Edit2: Even better, wait a few hours