This gun was not making loud reports when fired during a game I played recently.
Note: Another player was using Arty, his pistol was loud but his AR could not be heard until I was within a yard or so of him and even then it was not full volume.
Have not been able to recreate yet.
Update: Recreated this sound bug with the mounted turrets in a match just now.
Have a feeling this has something to do with my client, but not certain.