The chamber face seal on a Sheridan PGP, PMI 1, KP2 and other 12 gram pistols using the non cartridge valve seals a pierced 12 gram from leaking at the front of the 12 gram. But another common source of leaks is the oring on that sits around the chamber face.
In this video I install a new chamber face oring on a sheridan classic valve 12 gram face seal holder. The steel seal holder sits at the front of the valve and most times doesn’t need the oring replaced. This oring is a cheap part though so I often replace it when rebuilding a valve.
Find the Chamber face / valve casing oring here:
Sheridan seals and orings available here:
Find more classic paintball technical and product videos view this playlist: