You are right, of course i meant extract. I can not see the screw, there is a plug of copper or brass above it. I took the rifle to a gunsmith today. He checked the headspace with a headspace gauge, there is a small space left, but that may be normal to keep all kinds of ammo running. First of all he told me to replace the main spring. If this will not solve the problem the told me that he would taper the firing pin and then he would recommend to adjust the headspace.

Thank you for your continuous support.