got this a month ago. opened the box, cleaned it, had a quick try with it. fire button was hit and miss, slipped on ice on way to work this morning and damaged hip so have had some time to fiddle with it. only way i can get it to fire is to loosen (raise) the screw at the top of the fire button. it works but it's loose and after a while it stops firing and i have to loosen it again. seems replacing the magnet with a spring might fix this? anyone have any ideas or can suggest an appropriate spring if that's the way forward?