So, having a look through that script, it wouldn't actually do what you want. While it would disable some sounds you come across, it is a very small percentage (there are thousands of emitters and sound scenes in the game, but this script disables around 25), and doesn't actually disable the emitter that is used by the gun ranged. (the emitter used by the gun ranges is "LOS_SANTOS_AMMUNATION_GUN_RANGE")
If you look at the client.lua file on GitHub, you can have a check what it actually disables. Mostly cop sounds (which are mostly disabled already, vanilla unicorn sounds, and some random others.
Having a blanket scrip removing all the ambient sounds is a very bad idea. You don't realise how much of a difference they actually make until they are gone. It would be like playing the game on mute, but engine volume on 100%. Ever been to the docks, heard all the banging and sirens and dock sounds? They would be gone, for example.
I certainly agree that removing and emitter and audio scenes that are gunshots would be beneficial, mainly the one above for the gun range, but that can be added to an existing script, which ever already disables some sounds for example. While I don't play as AFO, I can certainly understand the issue, as when playing as civ even, going past the gun range, I panic where I hear them thinking I am about to be on top of someone's shot's fired scene, then remember that it's just the gun range.
