Good morning to everyone. I`m having a little bit of trouble with my johann faber apollo 43 piston filler. the thing is , when I unscrew it, the piston does not go all the way down the chamber , so when i`m going to fill it , the piston does not pull a full charge. when I`m screwing it the threads seem to skip and not push the piston all the way down This is how it should be: In order to do this i push the piston inside and then i put the cap. After this I screw it all the way in and tha cap retracts the piston normally and I can have a full charge. but when i unscrew the cap out again it does not push the piston down, like this.