Crossbow string rig

can somebody help me to rig the string ?
i’ve tried it multiple times but nothing seems to work
Crossbow Pre-Rig.blend (838 KB)

Crossbow Pre-Rig2.blend (848 KB)

I did one half for you. Keep in mind a bow string is pretty much perfectly straight, so you don’t need many bones for the string.

To tweak the way the arm works you can go into the bone properties and fiddle with the stiffness under the Inverse Kinematics tab.