Gday Lewis, was asked by a mate today if you could help out, he has one of these in 177
AT44-10 and air is leaking out of this bit
From the holes in the middle groove, we presume a seal has let go around the center shaft, question, what’s the go with getting it fixed, send to you ? I don’t want to pull anymore apart as I know sweet FA about the innards of them, it’s the plug/valve that goes into the inner end of his air tube resivoir

if you can help or steer us in the right direction I would appreciate it