Quote History Quoted:
It's the bolt on top of the barrel extension.
DO NOT TRY TO TAKE THE SPRING GUIDE ROD WHICH LOOKS LIKE A SCREW OUT OF THE BACK OF THE BOLT
It is under tremendous spring pressure and can shoot out like a .22!!!!!
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^THIS
That spring/guide rod has maimed, and almost killed people.
There was a thread about an individual who got one through the eye. Pictures were posted as well.
I cringed when I saw you took a picture directly behind it.
There isn't a positive lock where it is, it will simply launch out if turned.
I would SAFELY (look up how to safely remove) remove the rod/spring for storage and if you go with shipping to someone.