Air Venturi Barrel reassemble

[ratman1]

Hello,
I am reassembling the barrel on my avenger, and seem to have an extra part. It is a very tiny o ring. The only idea that I have is that it was under the large pointed barrel securing grub screw to help prevent over tightening the screw. Can someone let me know if I am correct?

Thank you

 

[darylm]

Might have fallen off of your pellet probe.

 

[ratman1]

Hi Darylm,
That was my first thought. It dos look about that size, but I still have them in place. The outside edge is scratched like the threads in the hole could cause. My thinking is Air Venturi has been having a problem with the grubs being tightened to much and dimpling the inside of the barrel, that they put it under the big pointed grub?

Is the transfer port "metal to metal" or could Come from there?

 

[ratman1]

I have found it. I guess I was correct about the grub screw. Number 4 on schematic
Thank you