wasn't doing much to lock the ball in.
It seemed to be in the wrong location.
I used my Demel tool to mill the hole out
about 0.5mm longer towards the ball
and now the bolt locks in better when closed.
With that tiny ball & weak spring, there is
no 'Click', but I can feel a bit of locking action.
I too have noticed that cocking screw gets loose as I shoot.
Since it has to come out for bolt O-ring cleaning etc.
I didn't want to use any loctite on it.
However, I'm testing Telfon tape on the threads now
and it does help some. Now when I check it after
shooting 40 shots, it's only 1/8 a turn loose

Maybe some kind of rubber glue could be used that
would not be hard to break when you wanted to..?.
Cheers,
Rich