Your research is correct, if the ring is cracked or broken the whole cocking tube housing needs to be replaced.

As it happens, when the original GSGs got discontinued part of the deal was that we were still allowed to do repairs on them with the balance of parts remaining at GSG.  Although we haven't been able to get original 5 parts since the 2010 agreement we made sure to try to hang onto ones for what limited original service we could provide without having to swap the changed parts to 522 parts.

If you would like this replaced, please contact our customer service department at 1-800-290-0065 option 3 or at [email protected].  We will require you to send the gun to us so that we are changing the part but we do still have a handful of original PK cocking tube housings available for customers just like you.  

And before anyone asks, we are not permitted to sell these parts to you if you do not have an original GSG-5 serial number that we can physically service at our facility, but hey, at least you know we're here for ya!

If you require service and have a 5 or 522 that needs parts, we can help you.  Just give us a call at 800-290-0065 or email us at [email protected] and have your serial number available and we'll see what we can do.  As far as sending in n NFA item for service....we were advised by ATF that customers with NFAs should transfer them to us on a Form 5 for repair (we can provide you instructions) and once approved we can bring it in and then the reverse to get it back to you.  Since being advised as such, this has been our policy for NFA repairs.