Looking for a Strange O-ring....

[emisnug]

Alright, so I have a Dangerous Power Threshold. Great when it decides to work. However. The back cap bumper o-ring has become dislodged. And therefore the bolt doesn't cycle properly. After various bits of internetting, it turns out that this is a pretty common probelm, and so I ask - does anyone have a bumper O ring that I can buy? Or, any knowledge on the bolt system of the Threshold?

Cheers

 

[NitroBall]

If you can look up the manual and see what size it is buddy ?

 

[emisnug]

It doesn't have one in the manual. (http://www.dangerouspower.com/downloads/manual/ManualThreshold.pdf) Which is why I am hugely confused. Just "Part #7". It is made out of O-ring material, but I'm not even 100% sure if its an O ring.