Retro Arms Hopup Unit Issues

[HuttArmouries]

So I recently got a retro arms cnc hop unit to replace the lemon in my lct rpk. With the hop turned off it seems to shoot fine but as soon as I add any pressure it jams every shot. ive tried it with both maple leaf and modify rubbers. 

 

[DerDer]

Did you check to make sure there are no burrs on the arm? Found it very picky with rubbers.

Have had good success with Prometheus purples with the Retro arms unit. 

Also did you change out the nozzle in your gearbox? It requires a longer nozzle than say a Lonex nozzle.

 

[HuttArmouries]

Did you check to make sure there are no burrs on the arm? Found it very picky with rubbers.

Have had good success with Prometheus purples with the Retro arms unit. 

Also did you change out the nozzle in your gearbox? It requires a longer nozzle than say a Lonex nozzle.

Click to shrink...

Currently it still has the stock lct nozzle in it. I didnt see anything in the listing or reviews which said it needed a longer one. guess that explains the issue. 

 

[DerDer]

That would stand a good chance of being the culprit. They recommend a 20.1mm air nozzle.