I don't think I have a problem with the firing pin. Its just that assuming you have your device unlocked and you are vaping. When I lock it by turning the locking ring counter clockwise, it sticks to the switch base and both get unscrewed from the tube. Then I put it in lock position and thread it back on the tube. Wait, do I have to hold the switch base with my other hand when locking?
I understand now, what you meant in the first place. When you change battery, it is better to do it from above. Adjust the telescopic centre post to create a tension to the battery, when the top cap is screwed down and with this method, the locking function won't interfere with the threading of the base of the switch and the tube. There is no need to hold the base with your other hand while you lock-unlock the switch. It is simply a matter of applying the right pressure to the battery via the telescopic centre post and changing the batteries from above.