Well, sometimes, maybe it helps to start over from scratch. In the course of making lots of little changes, maybe we have broken something important. If you still have your clean Xeno files, let's start from there.
Make these changes from "clean":
1) Edit Items.XML to change the AK47 from Normal to Unlimited
2) Edit Sounds.XML to add this:
<Sound name="Weapon AK Single" volume="1.0" group="1" comment=""> <Wave>audio/sfx/weapons/AK47_single.ogg</Wave> </Sound> <Sound name="Weapon AK Burst" volume="1.0" group="1" comment=""> <Wave>audio/sfx/weapons/AK47_burst.ogg</Wave> </Sound>
I would add that right after Weapon Shotgun Burst, as a convenient place to search for it in the file and find it again later.
3) Drop your sounds in the correct folder -> Assets/audio/sfx/weapons
4) Edit Weapons_GC.XML to edit the existing AK information for the sound to replace the single shot sound "Weapon Assault Rifle Single" with "Weapon AK Single" and the burst sound with "Weapon AK Burst". If you want to change the accuracy, TU, clip size and damage while you are here, go for it. I myself changed the "shot count" for the burst fire to 5, the suppression value was already greater than the M16 stats.
Test your game like this, before doing the other changes.
If that works fine (which I'm betting it does), then you can add the changed artwork to the correct locations and go back into Weapons_GC to set the name changes for the images. It might even be an issue with your artwork, which unfortunately, I can't offer much help with.