Sound Decay Bug
Not sure if client-side or a server setting thing. I can hear gunshots from within 5 feet of me as normal. Anything from 5 feet to 10 feet, sound rapidly decays, such that at 10+ feet I can barely hear anything, and at 20ish I can't hear them at all. Very weird behavior for guns, especially since they're meant to be loud as duck.
Have someone shoot a gun (P90 or HUGE for large mag) and have them walk away from you. Sound drops incredibly fast.