The only sound related line seems to live inside "attack_parameters"... Pretty sure all this has to be used somewhere else!The naming convention is "gunsound-"..gun.name.
Looping sounds are also supported but have a -begin_sound, -middle_sound, and -end_sound suffix.
...
game.player.surface.create_entity{name="gunsound-shotgun", position=game.player.position}
Any details on all this please?