Reptinus, I was looking at your texture and had a question. It looks like you have a frames in the version you currently have in the first post. Yet, each frame looks rectangular. The original frame was square. Wouldn't the texture then look a bit off?
I'll have to go look at it in game and then see if I can explain it better. (I am a big fan of animations. Love those TXIs!)
Pssst . . .
OK, your original non-animated texture looks like this.
Your animated texture looks (mostly) like this. I highlighted one frame with a green border and darkened the others for illustration purposes.)
The individual frame of animation must match the proportion of the original texture in order for it to not stretch. So, if you're using the first HK-47 picture as your template and it is sized as 512 x 512 - your TXI probably should probably be closer to this: