If you add your own gun you make one .x file that has all the animation in it and then tell the "gunspec.txt" file were each animation starts and ends. The gunspec file looks like this:
;COMMANDO weapon spec
;GUN Model File Requirements
;GUN Settings
muzzleflash = 1
muzzlesize = 50
brass = 2
smoke = 1
second = 0
damage = 10
damagetype = 1
scorchtype = 1
reloadqty = 24
iterate = 0
accuracy = 0
zoommode = 1
;GUN Visuals
textured =
effect =
transparency = 2
zoomscope = scope1.tga
weapontype = 3
;GUN Sounds
sound1 = fire.wav
sound2 = reload.wav
sound3 = dryfire.wav
sound4 = zoom.wav
sound5 =
fireloop = 4000
;HUD muzzleflash position
horiz = 0
vert = 0
forward = -2
alignx = 4
aligny = -2
alignz = 25
;HUD animation frames list
keyframe ratio = 1
select = 0,9
Idle = 10,38
Move = 39,53
Start fire = 54,56
automatic fire = 57,64
end fire = 65,70
reload = 71,107
cock = 108,123
putaway = 124,133
;HUD sound frames list
soundframes = 4
sframe0 = 57,1
sframe1 = 71,2
;sframe2 = 95,2
;sframe3 = 110,5
;sframe4 = 95,5