I have a Hatsan pcp stirrup pump that has developed a major problem.
When I attach it to a gun , the air pressure builds up in the pump, instead of transferring to the rifles cylinder . After 8 or nine pumps you can hardly pump it at all . It also freezes the inlet. Pulling up on the handles, it seems to create a vacuum and when letting go of the handle, it goes down on its own
There are no problems with the rifles inlet valve as I can fill it to 150 bar (All that is left in the tank, that's why I want to top it up with the pump) I topped it up yesterday morning before I went shooting. Then after the shoot, the pump worked for a few pumps then started doing this.
There are no blockages in the hose . If the filler probe is out of the rifle, it pushes air out like normal.
When you put your fingers over the holes of the filler probe , the pressure is there when you pump, and releases fine as soon as you take your fingers off. But if it is in the rifle and starts to build up pressure, the pressure builds up so high that handle doesn't move.
Any help as to what could be causing this problem and how to fix it would be appreciated .
(Mods please move this thread if it is in the wrong discussion)