airforce collapsible stock

You could run a press fit PVC pipe to slide over the bottle mount your contraption to it drill evenly spaced holes on top of the PVC and put an easily removeable nylon pin to anchor each position like a collapsible stock. Can even run a press fit double tube PVC sandwich your metal contraption in between both PVCs to keep it in place.
 
You could run a press fit PVC pipe to slide over the bottle mount your contraption to it drill evenly spaced holes on top of the PVC and put an easily removeable nylon pin to anchor each position like a collapsible stock. Can even run a press fit double tube PVC sandwich your metal contraption in between both PVCs to keep it in place.

Good idea...perhaps. My main concern is weight, so double sided sticky tape on the arms and then camo duct tape makes it immovable.
 
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