This mod from JoshuaC1 replaces most weapon firing sounds.
Better Weapon Sounds Beta 2
Replaces all weapon and grenade sounds with better sounding higher quality sounds. Tested with Clear Sky v1.5.04
but it should work with any version and possibly work just fine in any version of Shadow of Chernobyl.
All sounds have been ogg commented and are error free.
Beta 2 PKM sound added.
To install just extract the gamedata folder to your clear sky folder and make sure your fsgame.ltx has been edited to allow mods.
I take no credit for this soundpack as I didn't create the original sound files I just edited them per weapon and
went through the long annoying process of getting them properly commented. You can do whatever you want with them.