Why does it have to be pb specific!?
Not meaning to sound like a d**k but probably so there is some come back if something were to go wrong.
Having sent an Ego to a company in Leicester before, the gun was not usable upon return. It was stripped with great care, the parts were carefully packed and sent via a special courier.
A week later, the parts returned. At first everything looked fine.
The threads for the screws that held the solenoid on were actually damaged so could not be used, the body was warped and the anno was generally too thick so that the rammer housing was a slightly smaller diameter.
Sometimes, no matter how much you explain to somebody how you want something doing, you really should use somebody who has experience.