Quite often have lugers got their triggerpull adjusted by some d...head that don't know how it should be done.
And in order to minimize creep and weight in the triggerpull they have often grinded of the firing pin and or the sear.
This is ofcourse the absolutetly wrong way to adjust the engagement but it was a common way of doing this.
If that method is used there is very little engament left when the sear should catch the firing pin so the sear looses it's grip of the firing pin.
Only way of correcting this is either to install new parts, or to weld up the old parts with a welding wire that is hardend.
The problem could also be to weak searspring but I doubt that.
Only way of seirusly determine if the parts is grinded off is to measeure them up and compere them to the original drawings.
Regards HÃ?Â¥kan Spuhr
http://www.vapensmedjan.com