Hi Tony,

I think you would need to make a set of blueprints for your stock.
Measure all of the dimensions and angles.
It would help to have some reference points or planes, line the butt end.
Left view, right view, top view, bottom view, 2 end views, complete with measurements.

Here is how some guys made a 3D model of a laser rifle. http://www.3d-sphere.com/weapons/modeling-a-laser-rifle-in-3dsmax
http://kronosprops.blogspot.com/2010/03/aer9-laser-rifle-fallout-3-prop.html

Also have read that if you have a model of the action, you can boolean it out of the stock.

You could scan some precise photos, and import into moi as a help in making the blueprints...

I think autodesk has a free online program to create 3d models from some photos. Never used it...

Again, need the measurements...