Is it normal to hear air being released after a shot? Brocock Compatto, regulated.
Sounds like the air comes out at the back end where the hammer spring is.
There is likely to be a seal on the protruding shaft of the valve that is struck by the hammer.
I found a parts diagram on the web
- Bagnall and Kirkwood
See seals 4 and 54 on that diagram.
Somewhere there must be a list of corresponding part names....haven't found it yet.