Upgraded Ares striker 3 bolt doesn't catch?

[Novana]

Hi, wondered if any of you more experienced people could help me diagnose a problem.

 

I've been upgrading my AS03- i replaced the barrel, hop unit and rubber and spring without any trouble but I found it had significant variations in power (if frequently drops a few hundred FPS) which I think is due to a leaky cylinder. I've replaced the cylinder and nozzle with ones from FPS but now I'm finding the bolt doesn't catch properly. When I draw back the bolt the indicator extends as it should but then it doesn't lock and the bolt slides all the way back. I can't identify the cause of this issue and switching back to the old cylinder is not really an option because the FPS variability made it unusable.

 

Has anyone seen this issue before and know a fix?

 

Thanks