New air pistol . I filled the cylinder and attached it to the regulator, just at the last few turns the cylinder vented all the air out…down to nothing. I found a broken O Ring and replaced. It worked ok. Today I filled the cylinder and reattached and it emptied again to nothing. But this time the O Ring was not broken. I

What’s happening? I had put a drop of oil on the ring as advised. This is a new pistol. I’m annoyed.

G.