Umarex How to remove CO2 puncture Walther PPK bb?

[Bluemill]

In trying to do a complete rebuild of a Walther/Umarex PPK bb pistol I keep running into a roadblock. You can take apart the air valve fairly easily to a point- except the puncture piece which is beneath the CO2 mating gasket and brass retaining ring. Does anybody know the trick on this or is it non-serviceable? I have 4 old valves to sacrifice as "cadavers" to attempt the removal but why tear something up if it's non-repairable anyway. Any help on this would be appreciated!

Bluemill

 

[Felinis]

Why do you want to service the puncture piece?
Does it no longer puncture the CO2 cartridge?

Usually servicing is to repair the gun or refurbish it with new seals, cleaning and lubrication. Except for repair, this does not require disassembly of every part of the gun.

 

[marflow 777]

take of the brass retaining ring
https://www.airgunspares.com/gunspares/airgun-spares/umarex/ppk.html