Tested in multiplayer:
all players cant hear gunfire from m320, gm6 (and other weapons, i think, see same problem - http://feedback.arma3.com/view.php?id=12444), if distance to shooter => 650-700m. Specially tested on Altis, clear LOS, no obstacles, latest stable version.
All players can hear only crack sound for bullet, but no weapons sound.
Sound doesn't range far enough period. The main gun of a tank should be audible out to 20 kilometers on a calm day in the countryside. You can't even hear it at 500 meters. But you can hear the impact noise of the KE round, because that is so loud you can hear it over the entire map, for some reason.
The whole sound configs are out of whack right now, unfortunately.