Quote Originally Posted by Benelli B76 View Post
If you have a problem with only one pistol cylinder I would say it is a problem with its valve closing. The opposite can also happen when transferring too much liquid CO2 when you get valve block and need to use the venting cap. Any residual gas trapped between the extinguisher and cylinder when the lever is closed is at about 820 p.s.i. so it does make a noise.

Baz (see pic)

https://i.imgur.com/1ADwNgG.jpg
Hello Benelli76. I suspect is the shout off valve I changed the O ring but not get results inside there is one M3 brass wash I go to add other two to give more pressure on the spring.
when I lived in Italy I have one Benelli custom chambered 7.65 long barrel, and after became the b80 sport.
Thank you for your suggestion.
Katanga.