Necroing... 
I do't play Sins enough to want to mess with mods etc, original Rebellion is enough for me. But I was annoyed enough with the Kodiak's rattling gun sound that I searched for a mod that changes just that part and maybe the model too but could not find anything. I don't mind the model that much, it's actually got a certain appeal to it imo but that rattling autocannon sound, there's no excuse for it. Kodiaks are not peashooters, they do some decent damage and their guns should sound like it too. The Kol's autocannon firing sounds seem more appropriate imo. They sound like cannons and not firecrackers.
So I edit the Kodiak's game file so that it's autocannons look and sound like the Kol's and I'm happy with the results
I just copied the lines of text for weapon sound and animation from the Kol''s file to the Kodiak's file. If anyone as clueless as I was wants a quick fix this is how you do it:
1) download correct reference file version from https://forums.sinsofasolarempire.com/378266 It contains all the files needed to start some basic modding. You only need one little file from the zip but I don't know where to get just that file.
2) Find and extract the file called "FrigateTechHeavy.entity" It's the Kodiak's file. Open it with a text editor; I used Wordpad.
3) look for this block of text:
muzzleSounds
soundCount 2
sound "WEAPON_TECHCAPITALAUTOCANNONMEDIUM_MUZZLE_ALT1"
sound "WEAPON_TECHCAPITALAUTOCANNONMEDIUM_MUZZLE_ALT2"
hitEffectName "Weapon_Tech_AutoCannonFrigate_Hit"
hitHullEffectSounds
soundCount 1
sound "WEAPONIMPACT_PHYSICALMEDIUM_HITHULL"
hitShieldsEffectSounds
soundCount 1
sound "WEAPONIMPACT_GENERICMEDIUM_HITSHIELDS"
projectileTravelEffectName "Weapon_Tech_AutoCannonFrigate_Travel"
4) replace that whole block with this block:
muzzleSounds
soundCount 3
sound "WEAPON_TECHCAPITALAUTOCANNONHEAVY_MUZZLE"
sound "WEAPON_TECHCAPITALAUTOCANNONHEAVY_MUZZLE_ALT1"
sound "WEAPON_TECHCAPITALAUTOCANNONHEAVY_MUZZLE_ALT2"
hitEffectName "Weapon_Tech_AutoCannonCapShip_Hit"
hitHullEffectSounds
soundCount 1
sound "WEAPONIMPACT_PHYSICALHEAVY_HITHULL"
hitShieldsEffectSounds
soundCount 1
sound "WEAPONIMPACT_GENERICHEAVY_HITSHIELDS"
projectileTravelEffectName "Weapon_Tech_AutoCannonCapShip_Travel"
5) Save it. Then copy/move the edited "FrigateTechHeavy.entity" file to the "GameInfo" folder in your Sins install directory. On my computer the loaction is "C:\Program Files\Sins of a Solar Empire Rebellion\GameInfo"
This is not a mod you can select from the inagame mod list, I have no idea how to set one up. This just makes the game use the Kol's bullets and sounds for the Kodiak (correct me if I'm worng). Hope this helps some people.