not re-setting problem.

[Curss]

The flat spring that pushes down on the sear bar is called the sear bar spring. When you flip the safety on, it blocks the movement of this sear bar. Lugerdoc on the forums here should have some of the springs in stock, talk to him for it may be a weak sear bar spring. Also, check your firing pin and the contact point it has with the sear bar. My Luger was having a similar problem and low and behold, the firing pin had burs on the block that sticks out and contact the sear bar. Only when a round was being chambered would it actually charge the weapon. There are other ways to check the contact points in this area, someone here should know how.