The firing trigger animations don't seem to be working.

I managed to get it working for your FAL, but I had to steal a SWM MP5 to donate a trigger. I think the models are missing a trigger_axis point in the memory LOD, but even when I added it the animation screwed up (the trigger fell vertically back into the weapon from a great height with each shot).

You either have the axis on the wrong position or you have the rotation angle set to the wrong value.

For trigger axis (and all rotation anims): you need to add a namedproperty to your Lod to make all axes work correctly:

name: autocenter
value: 0

otherwise axes get shifted.