yeah take it to rayflip if ur not sure heel set ya straight on it.
I think it has to be your problem.
theres a way to check your bucking seal and thats by taking a dead battery and cycling your gun untill the airnozzle is fully extended, or just by short cycling it untill its extended. then take the barrel out of the upper and place it on the gun as if it was in the gun ready to go, plug the port in the cilinder, and blow down the end of the barrel if its airtight then its 100% a nub size problem.