Or you can do something much much easier and name the object mesh of the crystal 'crystal'and add hide node for 'crystal' into the script..
Create a node for the crystal and then use obj.hideNode("Crystal");
what the forget did you do to the stock
L4D2 M16, I'm a bit Rusty.
Holy forget knoz I'm willing to script those weapons for you if you don't have anybody yet.They're bloody awesome brilliant!