Something isn't right with guns. Modded servers may be accentuating the problem.
Many personal and anecdotal reports of unloading full mags into players which have no effect.
I often see my teammates guns floating above their backs - unsure if related.
I personally put 3 x .308 into a player from 600m and the player ran off uninjured.
Unclear at this stage
Update following testing:
I noticed I couldn't unpack a box of ammo. The circle indicator was starting but instantly stopping. I switched to a blank pistol and pressed the trigger repeatedly. My character looked to be trying to fire the pistol client side but my character was moving forward slightly like he was trying to punch server side.
Pressing G would not drop the gun.
I logged off and back on and I had nothing in my hand.
I expect there was never a gun in my hand and there was client/server de-synchronisation occurring
Tested on an official server and had the same bug occur.
Mainly after eating then switching to a gun