This tutorial assumes that you already done and understand the process of importing and animating a custom weapon for CODWAW. If you don't meet the requirement. Check out these well put video tutorials by Rollonmath42 to get a better understanding of the process.



The Goal
This is the goal we will try to achieve with the single pistol model.

Making Copy of Weapon
Import the pistol model you would like to dual wield into the Maya scene. In the video I'm using custom Halo Magnum pistol. Delete the bones that comes with the model. Save your scene and make a copy of it by going to edit then clicking copy. You wont be able to see the copy as it's in the same translation as the current one already on the scene. Using the outliner, select all the meshes of the copied pistol as use 20.5 on the Y-axis to position it for the Left Hands. And on the current scene pistol meshes, use -20.5 to position it for the right. The purpose is so that the pistols wouldn't be too far or too close from hands when rigging and when imported into game.

Rigging the Dual Wield
Rig the gun as you would any custom weapon by making its joints and positioning it to the appropriate mesh. You can mirror your translations as shown in video so that it'll be easier to position the bones to the opposite side pistol.

Importing Dual Wield to Animation Hands
Open your viewhands rig file and import you dual wields into the scene. Connect the j_gun bone to the tag_weapon bone as shown in video. Now go onto the normal process of custom animating by putting hands on weapons, positioning it for idle, etc.

Make weapons parent to hands for easier Animating(Optional)
The hands will now follow the right and left j_gun bones. As shown in video with the fire anim.

Finished Results. W.I.P.

http://youtu.be/H-tTNfxYi6s

Notes: Fx won't play from the right weapon and that will need to be fixed via script. Also the current way I'm rigging dual wields, I don't know if it's the right way or if there's a better way,etc. Just though I'd share how I done the process.

Credits:

Rollonmath42 - Video Tutorials
MakeCents - Idea's and Scripting